research article synthesis and properties of high strength...
TRANSCRIPT
Research ArticleSynthesis and Properties of High Strength Thin Film Compositesof Poly(ethylene Oxide) and PEO-PMMA Blend withCetylpyridinium Chloride Modified Clay
Mohammad Saleem Khan1 and Sabiha Sultana12
1National Centre of Excellence in Physical Chemistry University of Peshawar Peshawar 25120 Pakistan2Government College Women University Madina Town Faisalabad 3800 Pakistan
Correspondence should be addressed to Mohammad Saleem Khan saleemkhanupeshedupk
Received 25 March 2015 Revised 21 May 2015 Accepted 24 May 2015
Academic Editor Beng T Poh
Copyright copy 2015 M S Khan and S Sultana This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited
Ion-conducting thin film composites of polymer electrolytes were prepared by mixing high MW poly(ethylene oxide) (PEO)poly(methyl methacrylate) (PMMA) as a polymer matrix cetylpyridinium chloride (CPC) modified MMT as filler and differentcontent of LiClO
4by using solution cast method The crystallinity ionic conductivity (120590) and mechanical properties of the
composite electrolytes and blend composites were evaluated by using XRD AC impedance and UTM studies respectively Themodification of clay by CPC showed enhancement in the d-spacing The loading of clay has effect on crystallinity of PEO systemsBlend composites showed better mechanical properties Youngrsquos modulus and elongation at break values showed increase with saltand clay incorporation in pure PEO The optimum composition composite of PEO with 35 wt of salt and 33 wt of CPMMTexhibited better performance
1 Introduction
Polymerclay composites are hybrid materials which containorganically modified clay and polymer matrix These areextensively studied materials because of enhanced mechan-ical thermal optical and other properties The availabilityof clay its low cost and well developed intercalation chem-istry have added to attracting researchers towards materialpreparation from this Polymer molecules are believed tointercalate into the galleries of the clay [1] The amount ofclay in these composites plays a vital role in affecting polymercrystallinity and mechanical properties Pure nonmodifiedclay is difficult to intercalate and disperse homogeneously inthe polymer matrix because of high interfacial tension withorganicmaterials To overcome this problem clay ismodifiedto introduce hydrophobic character in itmaking intercalationwith polymers possible Organic modifier nature of polymerand processing conditions are major factors that affect thestructure of the resulting composite It has been indicatedthat the functional groups and chain length of the backbone
of organic modifier have vital influence on the d-spacingand elastic modulus of the polymer-clay composites andcrystallinity of polymers [1] Keeping this in mind theselection of polymer and organic modification of clay is veryimportant factor in preparation and use of such polymer-claycomposite
It is a well-known fact that poly(ethylene oxide) (PEO)is a unique polymer soluble in both aqueous and organicsolvents It has polyether chain which can coordinate withalkali cations (Li+ Na+ Ca2+ etc) resulting in the formationof polyelectrolyte for batteries supercapacitors and fuel cells[2ndash4] PEO based polyelectrolytes have been found to showlow conductivity while their blend with other polymers andincorporation of salts show enhancement in conductivity [5]The incorporation of clay having silicate layer is also knownto increase the conductivity of PEO based electrolytes Thecomposite of PEOClay has been studied in detail from timeto time [6ndash9] Most of the work so far has been done oncomposite containing only PEO-Clay On the other hand toour knowledge there are noor a few reports of PEO-PMMA
Hindawi Publishing CorporationInternational Journal of Polymer ScienceVolume 2015 Article ID 101692 10 pageshttpdxdoiorg1011552015101692
2 International Journal of Polymer Science
blend clay composites [10 11] and also the cetylpyridiniumchloride modified montmorillonite clay (CPMMT) has notbeen used to prepare such compositesThe present work aimsat the synthesis and characterization of PEO-PMMAClaycomposite with LiClO
4salt using cetylpyridinium chloride
modified montmorillonite clay The detailed X-ray diffrac-tion electrical and mechanical properties have been inves-tigated and discussed in the present work Further thin filmfabrication of these composites which has not been reportedearlier has been done and reported hereThis type of thin filmconfiguration may find application not only in solid polymerelectrolyte but also in shape memory polymers for improvedmechanical properties
2 Experimental
21 Materials Poly(ethylene oxide) (PEO) (MW 600000)and poly(methyl methacrylate) (PMMA) (high molecu-lar weight) were obtained from Acros and BDH Chemi-cals respectively The clay montmorillonite was purchasedfrom Aldrich Chemicals Research grade lithium perchlorateLiClO
4(MW10639) was obtained from Acros Chemicals
All these polymers and chemicals were used as such withoutfurther purification Acetonitrile (CH
3CN) was used as a
solvent It is a good solvent for polymers that is PEO andPMMA montmorillonite and salts
22 Methods
221 Modification of Clay One drawback to clay mineralsfor battery electrolytes is their hydrophilic nature Cationmodification is one way to avoid this issue Researchers areexploring organic cation and their ability tomake hydrophilicclays into organophilic compoundsThe term organic impliesthat organically modified clays can be attached to organicpolymersThe organic modification of clay in our system wascarried out according to the procedure reported earlier in theliterature [12]
222 Preparation of PEOSaltCPMMT and PEOPMMASaltCPMMT Composite Films PEO and PMMA were dis-solved separately in acetonitrile to prepare 2 solutionConstant volume of this 2 polymer solution was mixedwith different volumes of 1M LiClO
4and CPMMT following
continuous stirring for 24 h at 60∘C These solutions werethen transferred to Petri dishes of uniform diameter kept onsmooth and leveled surfaces covered with lids and were leftat room temperature for drying and converting into uniformsmooth films of PEOCPMMT (33 wt)Salt (21 35 and5wt) and PEOPMMACPMMT (33 wt)Salt (21 35and 5wt) polymeric composites designated as PCS21PCS35 PCS5 PPCS21 PPCS35 and PPCS5 respectivelyThe films obtained were stable and free standing
23 Instrumentation The X-ray diffractometry (XRD) wascarried out by using Cu-k120572 radiation at a tube voltage of40KV and 20mA current Rigaku (Japan) FX Geiger SeriesRAD B systemwas used for X-ray diffractionmeasurements
Table 1 Values of 119889-spacing for various systems studied
System Peak positionlowast(2120579) 119889-spacing
MMT 1165 75839CPMMT 1130 78266PEOCPMMTSalt (21 wt) 2295 38720PEOPCPMMTSalt (21 wt) 2285 38090lowastPeak with highest intensity
The tensile properties of the samples were tested usingTestometric universal testing machine M350500 manufac-tured by Testometric UK The films of pure polymers andthat of selected compositions of composites with uniformthickness (measuredwith digitalmicrometer) andwidthwerecut for analysis The length of each sample was 50mm Theanalysis was performed at room temperature with cross-headspeed of 5mmmin For high accuracy and precision a sen-sitive load cell of 100 kg capacities with 10mg load detectionwith a minimum 001mm cross-head speed was used Aspecial griping system was designed for thin film griping toavoid any slippage during tensile test Standard procedure andformulae were used for calculating various tensile propertiesincluding Young modulus (stiffness) and elongation at breakData directly feed into computer interfaced with the UTM
The impedance measurements were carried out at roomtemperature (15∘C) using Solartron 1260 frequency responseanalyzer (FRA) over the frequency range of 1minus1times107 Hz and100mv voltage The impedance data were then transferred tothe (Z-plotZ-view) software package
3 Results and Discussion
Montmorillonite clay (MMT) clay structure along with CPCstructure is shown in Figure 1 The structure shows thatan octahedrally coordinated alumina is sandwiched betweentwo tetrahedrally coordinated silica The spacing betweenclay layers ranges in nanometers and in between theselayers water molecules and exchangeable cations like Na+ arepresent These +Ve ions are mostly near the layers where theminusVe site of the layer is present and a kind of attachmentis there between these The CPC has a bulky cationic headand hydrocarbon chain which is neutral The MMT claywas modified with cetylpyridinium chloride (CPC) whosestructure is shown in Figure 2 The mechanism clearly showsthat smaller Na+ is exchanged with the bulky cationic headgroup of CPC while NaCl is coming out after treatmentDue to this exchange and insertion of larger cation inbetween layers the interlayer spacing increases (see Table 1)The modified clay that is CPMMT is organophilic with alower surface energy which is more compatible with organicpolymers
31 X-Ray Diffraction Analysis of PEOLiClO4(Constant)
CPMMT Composite System XRD of pure PEO shows max-imum diffraction peaks representing highly crystalline struc-ture as already published in our earlier studies [13] LiClO
4
International Journal of Polymer Science 3
H2O H2O H2O
H2O H2O H2O
Clminus
+ + +CH3
AluminumOxygenSilicon
Tetrahedral
TetrahedralOctahedral
Water andexchangeablecations
Cetylpyridinium chloride(CPC) is a surfactant usedfor organic modification
N+
Figure 1 Structure of MMT clay and CPC
NaCl
MMTCPC
CPMMT
Na+Na+ Na+ Clminus
CH3
N+
N+
N+
N+
N+
N+
N+
N+
N+
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
Na+ ClminusNa+
Figure 2 Mechanism of modification of MMT
XRDwas not done but as reported in literature XRD patternof LiClO
4shows intense peaks at angle 2120579 = 18360 2320
2750 32990 and 36580 revealing the crystalline nature ofthe ionic salt [14] Figures 3 and 4 display the XRD scan ofpure and CPC modified MMT respectively It is clear fromthe diffractogram and Table 1 that modification of clay byCPC enhances the d-value from 75839 to 782366 by shifting2120579 value from 1165 to 1130 It also shows the addition ofnew peaks at 2120579 = 1775 and 553 and vanishing of somepeaks at 2120579 = 208 424 5015 and 543 The addition and
disappearance of peaks and alteration of d-values clearlydepict the successful modification of montmorillonite byCPC The rest of the peaks are not altered The increasingd-spacing will cause the dissociation of MMT resulting incomposites with better dispersion of clay particles [15]
The polymersaltCPC modified structure and interac-tion mechanism is given in Figure 5 The interaction ofCPMMTwith polymer (PEO) shows that polymer moleculescome in between the CPC layers attached to clay An elabo-ration of the intercalating portion clearly shows that there is
4 International Journal of Polymer Science
0
500
1000
1500
2000
2500
0 10 20 30 40 50 60 70
Inte
nsity
(CPS
)
Pure MMTd-valueCPS
100398816398807589391272116544912711571975426686105820803354381592265525721557434852129973884240
199184124550181747303501516879529354301503173106165
2120579
2120579 (∘)
Figure 3 XRD scan of pure MMT
CPC modified MMT
9983272051885782366138311304992571303177544912712001975338419160126602572155803485199387523454516597730555301498793146185
0 10 20 30 40 50 60 700
500
1000
1500
2000
2500
Inte
nsity
(CPS
)
d-valueCPS2120579
2120579 (∘)
Figure 4 XRD scan of CPMMT
increase in gallery spacing which is associated with loweringin surface energy Polymer intercalates within the galleriesas a result of the negative surface charge and the cationichead groups of CPC preferentially reside on the layer surfaceThe salt that is LiClO
4has also interactions with both the
polymer and the negatively charged clay layersComposites of PEOLiClO
4CPMMT were synthesized
with 198 33 462 and 594wt of modified montmoril-lonite loading keeping the mole fraction of salt constantat 35 wt The diffraction patterns of PEOSaltCPMMT(198 (A) 33 (B) 462 (C) and 594 (D) wt) compositesystems are shown in Figure 6 It can be revealed from theseXRD patterns that the PEO has the minimum crystallinitywhen the CPMMT loading is 33 wt This 33 wt ofCPMMT loading was selected as an optimum condition forthe synthesis of the composites The substantial increase inthe intensities of the XRD peaks on increasing CPMMTloadings suggests that the dispersion is better at lower clayloading than at higher loadings This is because the lithiumcation coordinates with the flexible CH
2-O- chain of PEO
forming complexes and thereby disturbing the crystallinityWhen the clay is loaded into the PEOLi ClO
4electrolyte
the crystallinity initially decreases up to 33 wt of clayloading and increases thereafter In case of undoped PEOthe crystallinity gradually decreases with an increase in clayloading because of the steric hindrance caused by the hugesurface area of randomly oriented clay throughout thematrixThe different crystallization behaviors of PEOLiClO
4clay
composite electrolyte and PEOClay composite is explainedby considering the fact that negatively charged clay layers
also coordinate with the lithium cation due to a strongelectrostatic interaction The interaction depends on theexpansion of silicate layers and clay content Because of thisinteraction PEO to Li+ interactions decrease and crystallinityincreases Thus two competing effects are present in thePEOLiClO
4Clay composite electrolyte one reduces the
crystallinity and the other favors the crystallinity At low clayloading the first factor predominates leading to a decrease inthe crystallinity and beyond the optimumclay concentrationsthe second factor predominates over the first resulting inhigher crystallinity [16 17] The presence of the CPMMThowever had no effect on the location of the peaks whichindicates that perfect exfoliation of the clay layer structureof the organoclay in PEO does not occur [18] The XRDpatterns of the fabricated composites show that most of thepeaks corresponding to pure LiClO
4have disappeared in the
composite system which reveals the dissolution of the saltin the polymer matrix Similarly the appearance of some ofthe peaks of the LiClO
4in the composite system confirms the
complexation of the salt with the polymer matrix
32 X-Ray Diffraction Analysis of PEOLiClO4(Variable)
CPMMT(33 wt) Composite System X-ray diffraction anal-ysis of PEOLiClO
4CPMMT composite with 33 wt of
CPMMT clay at varying concentrations of salt is shown inFigure 7 which depicts that PEOLiClO
4clay composites
first show decrease in crystallinity of PEOwith the increasingamount of salt but when the concentration of salt is increasedfrom PCS2 that is 35 wt the crystalline character of PEOstarts increasing this is attributed to the local aggregationof inorganic particles at higher salt concentration The sameresult ismanifested by ourmechanical and Scanning ElectronMicroscopy (SEM) studies
33 X-Ray Diffraction Analysis of PEOPMMALiClO4(Vari-
able)CPMMT(33 wt) BlendComposite System In order toinvestigate the effect of poly(methyl methacrylate) (PMMA)addition on the crystallinity of PEO in the blend compositeof PEOPMMALiClO
4CPMMT having variable concentra-
tions of salt and constant clay content (of 33 wt) X-rayanalysis was carried out From the diffractogram patterngiven in Figure 8 it is clear that though PMMA is amorphousin nature its addition to the composite system has no sig-nificant effect on the system The crystalline fraction of PEOincreased a little bit by its additionThis is because the amountof PEO in PEOPMMA blend is far more than overlap weightfraction (119882lowast) which causes PEO to crystallize and alsobecause PMMA interaction with CPMMT is more than thatof PEO which affects the properties of PEO when present inblendThe d-spacing between the layers of the system is foundto be decreasing (Table 1) which also accounts for increaseof crystalline behavior This result is consistent with our ACimpedance study and is also supported by the literature [18]
34 Ionic Conductivity of PEO Composite and Blend Compos-ite System In a Nyquist impedance plot the real part (119885) ofthe impedance was plotted against the imaginary part (119885)for data collected at frequencies ranging from 1 to 107Hz
International Journal of Polymer Science 5
OO
OO
OO
O
O
O
OO
O
O
OO
OO
OO
O
O
O
OO
O
O
OO
O
O
OO
OO
O
O
OO
O
O
OO
OO
O
O
OO
OO
O
O
OO
O
O
OO
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+N
+
N+
N+
N+
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+
N+
N+
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+N
+
N+
N+
N+
CH3 CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3 CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3 CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3CH3
CH3
CH3CH3CH3CH3
CPMMT Polymer
O O O
O
O O OO
O
O
O O
O
O
OO
OOO
O
OOOO
O
O
OO
O
O
OO
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
N+
N+
N+
CH3 CH3
CH3CH3
LiCIO4
OOO
O
OOOO
O
O
OO
O
O
OO
O O O
O
O O OO
O
O
O O
O
O
OO
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3 N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3 N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N
+
CH3N
+
CH3N
+
CH3N
+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N
+
CH3N
+
CH3N
+
CH3N
+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
Li+
CIO4minus
NN+
NN+
CH3
NN+
3
NNNNNN
CHC 3
NNN
CHC 3
CHC 3 NNN+
CH3
NNN+
CH3
NNN+
CH3
NNN+
CH3
NN+
CH3
NN+
CH3
NN+
CH3
NN+
CH3
NNN++
CH3
NNN++
CH3
NNN++
CH3
NNN++
CH3
NNN+
CHC 3
NNN+
CHC 3
NNN+
CHC 3
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
Figure 5 Mechanism of PEO-SaltCPMMT interaction
To investigate complete picture of the system an equivalentcircuit was used [19]The bulk resistance of the solid polymerelectrolyte (SPE) was consequent from the equivalent circuitFigures 9(a) 9(b) 9(c) and 9(d) show theNyquist impedanceplots for PEOLiClO
4 denoted as PS (a) PEOLiClO
4
after fitting to equivalent circuit (b) PEOCPMMTLiClO4
denoted as PCS (c) PEOPMMACPMMTLiClO4denoted
as PPCS (d) and impedance plot after fitting to the equiv-alent circuit respectively These diagrams deviate from anideal impedance spectrum that usually exhibits a standardsemicircle at the high frequency section and a vertical lineat a lower frequency section The deformed semicircle andthe inclined line for the polymeric filmelectrode systemmay be attributed to the irregular thickness and morphologyof the polymeric film and the roughness of the electrodesurface [20 21] To investigate the phenomenon a ldquoconstantphase elementrdquo (CPE) was employed in the equivalent circuitThe high frequency semicircle depicts the combination ofR1 and CPE-1 while the spike showing the trend for second
semicircle due to double layer capacitance (at the interface ofsolid polymer electrolyte and electrode) is reflected by CPE-2 [19] The equivalent circuit used for fitting data and tablefor parameters for the circuit elements evaluated by fittingthe impedance data for composite and blend system at roomtemperature (15∘C) is given in Figure 9 as inset
From equivalent circuits the bulk resistance values wereobtained The bulk resistance allows us to obtain the ionicconductivity using
120590 =
119868
119877119860
(1)
where 120590 = conductivity (Scm) 119877 = resistance (Ω) 119868 =thickness (cm) and 119860 = area of the electrode (cm2)
The capacitance values were calculated according to120596max119877119862=1 (2)
where 120596max corresponds to the frequency at the maximum ofsemicircle The capacitance values obtained for the bulk arein complete harmony with the earlier reported values [22]
6 International Journal of Polymer Science
(A)
(B)
(C)
(D)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 6 Combined XRD pattern of PEOSalt composite systemwith 198 (A) 33 (B) 462 (C) and 594 (D) wt of CPMMT
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 7 Combined XRD scans of PEOCPMMTSalt (PCS1)(21 wt A) PEOCPMMTSalt (PCS2) (35 wt B) and PEOCPMMTSalt (PCS3) (5 wt C)
The value of ionic conductivity obtained at room tem-perature (15∘C) for pure poly(ethylene oxide) (PEO) is lessthan 678 times 10minus10 S cmminus1 reported in the literature earlier byKumar and coworker [17] for the samemolecular weight PEOat 30∘C This difference in conductivity values is because ofthe temperature and changing nature of solvent used in ourstudy [23] From the table given as inset in Figure 10 it isclear that the conductivity of PEO at laboratory temperaturethat is 15∘C increases sharplywith the salt incorporationThe
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 8 Combined XRD scans of PEOPMMACPMMTSalt(PPCS1) (21 wt A) PEOPMMACPMMTSalt (PPCS2) (35 wtB) and PEOPMMACPMMTSalt (PPCS3) (5 wt C)
same trend in conductivity of PEO based electrolytes withthe salt concentration has also been observed by Srivastavaand Ibrahim et al [24 25] This increase is due to theincrease in charge carriers caused by the addition of higherconcentration of LiClO
4and the increase in the fraction of
amorphous phaseThe addition of ionic salt decreases degra-dation temperature because of the growth of amorphous frac-tion and destabilizes the polymer network The PEOLiClO
4
electrolyte with high salt concentration was found to be lessstable Alternatively CPMMT was used to overcome thesedrawbacks Inorganic fillers are usually used to improvethe electrochemical and mechanical properties [26] Clay isinorganic filler with intercalation property where clay layersmaintain their registry Intercalating polymer (residing poly-mer chains between silicates) in a layered clay host can pro-duce huge interfacial area to sustain the mechanical propertyof polymer electrolyte system and impart salt solvating powerto dissolve the lithium salt [27] A glance at Figure 10 and insettable reveals that the addition of salt at constant (33 wt)clay content increases the conductivity of PEOSaltCPMMT(PCS) composites retaining dimensional stability till PCS2(35 wt) beyond PCS2 further addition of salt decreases theconductivity badlyThis initial increase is due to the decreasein the crystallinity and increase in amorphous fraction ofPEO for ion conduction till equilibrium is achieved at PCS2This is consistent with our XRD results The conductivitydecreases drastically when amount of salt increases fromPCS2 to PCS3 (5wt) but is still higher than that of pristinepolymer The possible explanation for this behavior may beion association and the formation of charge multipliers [25]In order to study the effect of poly(methyl methacrylate)(PMMA) incorporation on the ionic conductivity of PEObased solid polymer electrolytes PMMA was blended with
International Journal of Polymer Science 7
1e6 2e6 3e6 4e600
minus1e6
minus2e6
minus3e6
minus4e6
Z998400
PEOLiClO4
N998400998400
(a)
Samples PS PCS PPCS661410 169520
CPE1-TCPE1-P 0922 09848 0535CPE2-TCPE2-P 0864 0715 08156
50000 100000 15000000
minus50000
minus100000
minus150000
Z998400
R1Ω 127 times 106
965 times 10minus11
544 times 10minus11
622 times 10minus11
946 times 10minus9
882 times 10minus9
877 times 10minus10
CPE1CPE2 CPE2R1
N998400998400
(b)
1e6 2e6 3e6 5e64e60
Z998400
0
minus1e6
minus2e6
minus3e6
minus5e6
minus4e6
PEOCPMMTLiClO4
N998400998400
(c)
1e7 2e7 3e70
Z998400
0
minus1e7
minus2e7
minus3e7PEOPMMACPMMTLiClO4
N998400998400
(d)
Figure 9 Typical Nyquist impedance plots for PEOSalt (PS) (a) PEOSalt (PS) after fitting to equivalent circuit (b) Inset showing thatdiagram of circuit and extracted parameters for the circuit elements of PS PCS and PPCS are summarized in the table PEOSaltCPMMT(PCS) (c) PEOPMMASaltCPMMT (PPCS) (d)
PEO for solid polymer electrolyte (SPE) composites Fromthe values of ionic conductivity given in Figure 10 and insettable it is clear that the addition of PMMA to PEOSaltelectrolyte system decreases the conductivity of PCS systembut still shows higher value than pure PEO films The rigidstructure of PMMA due to the entrapped silicate layersalters the segmental dynamics of PEO so there is decreasein conductivity Jeddi and coworkers [28] have reported anoverlapweight fraction for PEOPMMAblendwhich is about28 wt for PEO Overlap weight fraction is that weight atwhich PEO starts interpenetration and miscibility of blendsis affected In our system the amount of PEO is far more thanoverlap weight fraction So it causes decrease in conductivityand an increase in the agglomeration of clay by decreasing itsinteraction with the PEOThe same trend has been observed
in mechanical properties of the PEOPMMASaltCPMMT(PPCS) composites The values of ionic conductivity wereached at laboratory temperature of 15∘C are higher thanthose reported for the PEOPMMAsaltNa-MMT in theliterature at 25∘C [22] This increase may be caused by thebetter dispersion of CPMMT
35 Elongation at Break of PEOLiClO4CPMMT Composite
System Elongation at break is the strain at failure or percentchange at failure and explains the ductility of the materialwith external forceThe effect of salt addition on the ductilityor elongation is shown in Figure 11 The result fromFigure 11 depicts that ductility of the composite materialincreases with increasing salt concentration in the resultingcomposites This increase is attributed to the presence of
8 International Journal of Polymer Science
0 1 2 3 4 5 6
PPSCPSC
Salt concentration (wt)
Film codeP0PCPCS1PCS2PCS3PPCS1PPCS2PPCS3
minus1
minus7
minus8
minus9
minus10
minus11
minus12
726 times 10minus12
1017 times 10minus7
5 times 10minus10
294 times 10minus8
556 times 10minus11
220 times 10minus10
424 times 10minus9
331 times 10minus9
Bulk 120590 (Scm)
Log120590
(S cm
minus1)
Figure 10 Bulk ionic conductivity variation for PSC and PPSCwithweight of salt for composite system at room temperature (15∘C)
0
100
200
300
400
500
600
0
5
10
15
20
25
0 1 2 3 4 5 6Salt concentration (wt)
minus1
Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
clay)
syste
m
and
(PEO
+PM
MA+
clay)
PEO + clay
PEO + PMMA
PEO + PMMA + clay Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
PMM
A)
Figure 11 Variation of elongation at break for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
CPMMT which enhances the mobility of the PEO polymerThe highest elongation at break is obtained for the PCS2composite and beyond PCS2 elongation at break decreasesThe higher uniformity in the dispersion of salt and claywithin PEO is correlated with better adhesion between thecomponents of the composite due to the homogeneousdispersion of CPCMMT at PCS2 composition The decreasein the ductility beyond PCS2 is due to the restriction inchain mobility of the matrix and the filler particles acting asdefect points [29] This also shows that beyond certain limitof salt concentration the behavior changes Further at higher
20
40
60
80
100
120
140
160
0
200
400
600
800
1000
0 1 2 3 4 5 6Salt concentration (wt)
PEO + clay
PEO + PMMA
PEO + PMMA + clay
minus1
s mod
ulus
(Nm
m2) f
or (P
EO+
clay)
syste
mYo
ungrsquo
s mod
ulus
(Nm
m2)
and
(PEO
+PM
MA+
clay)
for (
PEO+
PMM
A)
Youn
grsquo
Figure 12 Variations of Youngrsquos modulus for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
concentrations the polymers exist in agglomeration and theclay is not well dispersed The overall result is the increasein the ductility of the composite material with increasingsalt concentration The net increase in elongation at breakfor PCS system suggests filler induced dimensional stabilityto the composite electrolyte films making them capable ofsustaining and withstanding any external pressureshock to abetter level
36 Youngrsquos Modulus of PEOLiClO4CPMMT Composites
Youngrsquos modulus is a variable that describes the relationshipof stress to strain within the elastic region This is measuredfrom the slope of the curve within the elastic area of thespecimen The modulus of elasticity describes a materialrsquosstiffness the greater the modulus the stiffer the material Itquantifies the elasticity of the polymerIt is truly associatedwith primary and secondary chemical bonds Unlike the neatpolymer where the mechanical properties are determinedalmost entirely by matrix the mechanical properties of thecomposite depend on the interaction between the polymerand the added fillers From Figure 12 it is clear that Youngrsquosmodulus of the composites electrolyte decreases with theincreasing concentration of inorganic contents at constantclay levelThe influence of LiClO
4on the mechanical proper-
ties of PEOCPMMT film resembles the plasticization effectThe interaction between PEO and CPMMT is weakened bythe increasing content of salt The same behavior of Youngrsquosmodulus with filler has been reported earlier in the literature[29] As mechanical properties change by changing thecomposition of components as well as with the applied forcethey are difficult to analyze Also this decrease may probablybe explained in terms of debonding around polymer andclay interphases and void formation It can be concluded thatvalue of modulus depends highly on the distribution of fillerparticles in the polymer matrix which in turn depends on
International Journal of Polymer Science 9
the particleparticle interaction (agglomeration) andpolymerparticle interaction (adhesion and wetting) and morphologyof the filler particles [30]
37 Elongations at Break of PEOPMMALiClO4CPMMTBlend Composites System In order to have a more clear ideaof the change inmechanical properties of the blend compositesystem first the addition of salt to the blend system wasstudied for its effect on the mechanical properties and thenCPMMT was added to the same system and the sampleswere analyzed by UTM From the results given in Figure 11it is clear that elongation at break decreases initially withthe increasing concentration of salt to the blend system andthen starts increasing with higher salt concentration Thisdecrease in failure strain is due to the rigid filler additionwhich restricts the mobility of the PEO polymermolecules toflow freely past one another thus causing premature failureThe original elasticity of PEO is distorted due to the additionof PMMA and LiClO
4which is in close agreement with the
conclusion that the addition of rigid particles like PMMAinto the polymer matrix increases its stiffness and toughness[31 32] Compositeswith these properties can be used for heatresistant materials or product packaging materials
38 Youngrsquos Modulus of PEOPMMALiClO4CPMM Blend
Composites System Youngrsquos modulus of the PEOPMMA asa function of salt is shown in Figure 12 From this Figure itis clear that Youngrsquos modulus of the blend composite showsan overall decrease with the addition of salt This decreaseshows the weaker PEO interchain interaction and increasein the particle size of the inorganic phase because of localaggregations of particles in the presence of PMMA thesephenomenamay act as flaws in it [33 34]The same trend hasbeen confirmed by the SEM result as well This means thatthe addition of salt to the PEOPMMA composite suppressesthematerialrsquos stiffness and hence elasticity of the polymer Butwhen clay was added to the same PEOPMMASalt systeman enormous increase in the value of Young modulus wasobserved as shown in Figure 12 This is due to the interca-lation of polymer chains within the clay galleries that avoidsegmental motion of the polymer chains [35] Although thereis an overall decrease in the value of Young modulus of thePEOPMMALiClO
4CPMMT system with increasing salt
concentration still it is much higher than that of the virgin(neat) poly(ethylene oxide) (PEO) and PEOSaltCPMMTThis is in close agreement with the conclusion that theaddition of rigid particles like PMMA into the polymermatrix increases its stiffness [31]
4 Conclusions
This work used cetylpyridinium chloride to modify MMTmixed with higher molecular weight PEOLiClO
4and
PEOPMMALiClO4to produce composite materials The
experimental results showed that at constant salt contentthe addition of CPMMT first reduces crystallinity of PEOtill 33 wt of clay and then starts increasing at higher claycontent Thus 33 wt of clay was selected as the optimum
clay loadings for composites fabrication The XRD resultsshowed that the crystallinity of composites at optimum clayloading increases with increasing salt content and ionicconductivity obtained from impedance technique showeddeclining trend with higher salt content The addition of50wt of higher molecular weight PMMA to the com-posite of PEOSaltCPMMT affected the properties due tothe immiscibility or aggregation of filler within the poly-mer matrix however the blend composites showed bettermechanical performanceThe composite of PEOwith 35 wtof salt and 33 wt of CPMMT exhibited better performance
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] S Sultana Fabrication and studies on thin film composites ofPoly (Ethylene Oxide) [PhD thesis] University of PeshawarPeshawar Pakistan 2013
[2] T Lan P D Kaviratna and T J Pinnavaia ldquoEpoxy self-polymerization in smectite claysrdquo Journal of Physics and Chem-istry of Solids vol 57 no 6-8 pp 1005ndash1010 1996
[3] X Q Yang H S Lee L Hanson J McBreen and Y OkamotoldquoDevelopment of a new plasticizer for poly(ethylene oxide)-based polymer electrolyte and the investigation of their ion-pairdissociation effectrdquo Journal of Power Sources vol 54 no 2 pp198ndash204 1995
[4] R Mishra and K J Rao ldquoElectrical conductivity studies ofpoly(ethyleneoxide)-poly(vinylalcohol) blendsrdquo Solid State Ion-ics vol 106 no 1-2 pp 113ndash127 1998
[5] M S Khan A Shakoor and J Nisar ldquoConductance study ofpoly(ethylene oxide)- and poly(propylene oxide)-based poly-electrolytesrdquo Ionics vol 16 no 6 pp 539ndash542 2010
[6] Z Shen G P Simon and Y-B Cheng ldquoComparison ofsolution intercalation and melt intercalation of polymer-claynanocompositesrdquo Polymer vol 43 no 15 pp 4251ndash4260 2002
[7] P Aranda and E Ruiz-Hitzky ldquoNew polyelectrolyte materialsbased on smectite polyoxyethylene intercalation compoundsrdquoActa Polymerica vol 45 no 2 pp 59ndash67 1994
[8] D Ratna S Divekar A B Samui B C Chakraborty and AK Banthia ldquoPoly(ethylene oxide)clay nanocomposite thermo-mechanical properties andmorphologyrdquo Polymer vol 47 no 11pp 4068ndash4074 2006
[9] D Ratna S Divekar S Patchaiappan A B Samui and BC Chakraborty ldquoPoly(ethylene oxide)clay nanocomposites forsolid polymer electrolyte applicationsrdquo Polymer Internationalvol 56 no 7 pp 900ndash904 2007
[10] S K Lim JW Kim I Chin Y K Kwon andH J Choi ldquoPrepa-ration and interaction characteristics of organically modifiedmontmorillonite nanocomposite with miscible polymer blendof poly(ethylene oxide) and poly(methyl methacrylate)rdquo Chem-istry of Materials vol 14 no 5 pp 1989ndash1994 2002
[11] Y H Hyun S T Lim H J Choi and M S Jhon ldquoRheologyof poly(ethylene oxide)organoclay nanocompositesrdquo Macro-molecules vol 34 no 23 pp 8084ndash8093 2001
10 International Journal of Polymer Science
[12] H-W Chen C-Y Chiu and F-C Chang ldquoConductivity en-hancement mechanism of the poly(ethylene oxide)modified-clayLiClO
4systemsrdquo Journal of Polymer Science Part B Poly-
mer Physics vol 40 no 13 pp 1342ndash1353 2002[13] S Sultana M S Khan and M Humayun ldquoPreparation mor-
phology and thermal and optical properties of thin films offerric chloridepolyethylene oxide compositesrdquo Turkish Journalof Chemistry vol 36 no 5 pp 709ndash716 2012
[14] R Baskaran S Selvasekarapandian N Kuwata J Kawamuraand T Hattori ldquoConductivity and thermal studies of blendpolymer electrolytes based on PVAc-PMMArdquo Solid State Ionicsvol 177 no 26-32 pp 2679ndash2682 2006
[15] S K Lim S T Lim H B Kim I Chin and H J Choi ldquoPrepa-ration and physical characterization of polyepichlorohydrinelastomerclay nanocompositesrdquo Journal of MacromolecularScience Part B Physics vol 42 no 6 pp 1197ndash1208 2003
[16] B Chen and J R G Evans ldquoPreferential intercalation inpolymer-clay nanocompositesrdquo Journal of Physical Chemistry Bvol 108 no 39 pp 14986ndash14990 2004
[17] B Kumar and L G Scanlon ldquoPolymer-ceramic compositeelectrolytes conductivity and thermal history effectsrdquo SolidState Ionics vol 124 no 3 pp 239ndash254 1999
[18] J-H Chang S J Kim Y L Joo and S Im ldquoPoly(ethyleneterephthalate) nanocomposites by in situ interlayer polymeriza-tion the thermo-mechanical properties and morphology of thehybrid fibersrdquo Polymer vol 45 no 3 pp 919ndash926 2004
[19] X Qian N Gu Z Cheng X Yang E Wang and S DongldquoImpedance study of (PEO)
10LiClO
4-Al2O3composite polymer
electrolyte with blocking electrodesrdquo Electrochimica Acta vol46 no 12 pp 1829ndash1836 2001
[20] G J Brug A L G Van den Eeden M Sluyters-Rehbach and JH Sluyters ldquoThe analysis of electrode impedances complicatedby the presence of a constant phase elementrdquo Journal ofElectroanalytical Chemistry and Interfacial Electrochemistry vol176 no 1-2 pp 275ndash295 1984
[21] F Bellucci M Valentino T Monetta et al ldquoImpedance spec-troscopy of reactive polymers 1rdquo Journal of Polymer SciencePart B Polymer Physics vol 32 no 15 pp 2519ndash2527 1994
[22] J T S Irvine D C Sinclair and A R West ldquoElectroceramicscharacterization by impedance spectroscopyrdquo Advanced Mate-rials vol 2 no 3 pp 132ndash138 1990
[23] K V Kumar and G S Sundari ldquoConductivity studies of(PEO +KHCO
3) solid electrolyte system and its application
as an electrochemical cellrdquo Journal of Engineering Science andTechnology vol 5 no 2 pp 130ndash139 2010
[24] P C Srivastava in Solid State Ionics Materials and ApplicationsB V R Chowdar Ed pp 561ndash565 World Scientific Singapore1992
[25] S Ibrahim and M R Johan ldquoConductivity thermal andneural networkmodel nanocomposite solid polymer electrolytesystem (PEO-LiPF6-EC-CNT)rdquo International Journal of Elec-trochemical Science vol 6 no 11 pp 5565ndash5587 2011
[26] P P Chu M J Reddy and J Tsai ldquoStructural and transportcharacteristics of polyethylene oxidephenolic resin blend solidpolymer electrolytesrdquo Journal of Polymer Science Part B Poly-mer Physics vol 42 no 21 pp 3866ndash3875 2004
[27] H-W Chen C-Y Chiu and F-C Chang ldquoConductivityenhancement mechanism of the poly(ethylene oxide)modi-fied-clayLiClO
4systemsrdquo Journal of Polymer Science Part B
Polymer Physics vol 40 no 13 pp 1342ndash1353 2002
[28] K Jeddi N T Qazvini S H Jafari and H A KhonakdarldquoEnhanced ionic conductivity in PEOPMMA glassy misci-ble blends role of nano-confinement of minority componentchainsrdquo Journal of Polymer Science Part B Polymer Physics vol48 no 19 pp 2065ndash2071 2010
[29] S Ramesh and N B Khoo ldquoConductivity mechanical andthermal studies on poly(methyl methacrylate)-based polymerelectrolytes complexed with lithium tetraborate and propylenecarbonaterdquo Journal of Materials Engineering and Performancevol 21 no 1 pp 89ndash94 2012
[30] F Ali Synthesis and characterization of polyimidesilicabased nano-composites material [MPhil Thesis] University ofPeshawar Peshawar Pakistan 2006
[31] S Bai J Chen Z Huang and Z Yu ldquoThe role of the interfacialstrength in glass bead filled HDPErdquo Journal of Materials ScienceLetters vol 19 no 17 pp 1587ndash1589 2000
[32] G Nasar Synthesis and characterization of poly (vinyl alcohol)composites [MPhil thesis] University of Peshawar PeshawarPakistan 2008
[33] A Bandyopadhyay M de Sarkar and A K BhowmickldquoPoly(vinyl alcohol)silica hybrid nanocomposites by sol-geltechnique synthesis and propertiesrdquo Journal of Materials Sci-ence vol 40 no 19 pp 5233ndash5241 2005
[34] H B Kim J S Choi C H Lee S T Lim M S Jhon andH J Choi ldquoPolymer blendorganoclay nanocomposite withpoly(ethylene oxide) and poly(methylmethacrylate)rdquo EuropeanPolymer Journal vol 41 no 4 pp 679ndash685 2005
[35] R L Ledoux and J L White ldquoInfra red studies of hydrogenbonding interaction between kaolinite surfaces and intercalatedpotassium acetate hydrazine formamide and ureardquo Journal ofColloid and Interface Science vol 21 pp 27ndash52 1996
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
2 International Journal of Polymer Science
blend clay composites [10 11] and also the cetylpyridiniumchloride modified montmorillonite clay (CPMMT) has notbeen used to prepare such compositesThe present work aimsat the synthesis and characterization of PEO-PMMAClaycomposite with LiClO
4salt using cetylpyridinium chloride
modified montmorillonite clay The detailed X-ray diffrac-tion electrical and mechanical properties have been inves-tigated and discussed in the present work Further thin filmfabrication of these composites which has not been reportedearlier has been done and reported hereThis type of thin filmconfiguration may find application not only in solid polymerelectrolyte but also in shape memory polymers for improvedmechanical properties
2 Experimental
21 Materials Poly(ethylene oxide) (PEO) (MW 600000)and poly(methyl methacrylate) (PMMA) (high molecu-lar weight) were obtained from Acros and BDH Chemi-cals respectively The clay montmorillonite was purchasedfrom Aldrich Chemicals Research grade lithium perchlorateLiClO
4(MW10639) was obtained from Acros Chemicals
All these polymers and chemicals were used as such withoutfurther purification Acetonitrile (CH
3CN) was used as a
solvent It is a good solvent for polymers that is PEO andPMMA montmorillonite and salts
22 Methods
221 Modification of Clay One drawback to clay mineralsfor battery electrolytes is their hydrophilic nature Cationmodification is one way to avoid this issue Researchers areexploring organic cation and their ability tomake hydrophilicclays into organophilic compoundsThe term organic impliesthat organically modified clays can be attached to organicpolymersThe organic modification of clay in our system wascarried out according to the procedure reported earlier in theliterature [12]
222 Preparation of PEOSaltCPMMT and PEOPMMASaltCPMMT Composite Films PEO and PMMA were dis-solved separately in acetonitrile to prepare 2 solutionConstant volume of this 2 polymer solution was mixedwith different volumes of 1M LiClO
4and CPMMT following
continuous stirring for 24 h at 60∘C These solutions werethen transferred to Petri dishes of uniform diameter kept onsmooth and leveled surfaces covered with lids and were leftat room temperature for drying and converting into uniformsmooth films of PEOCPMMT (33 wt)Salt (21 35 and5wt) and PEOPMMACPMMT (33 wt)Salt (21 35and 5wt) polymeric composites designated as PCS21PCS35 PCS5 PPCS21 PPCS35 and PPCS5 respectivelyThe films obtained were stable and free standing
23 Instrumentation The X-ray diffractometry (XRD) wascarried out by using Cu-k120572 radiation at a tube voltage of40KV and 20mA current Rigaku (Japan) FX Geiger SeriesRAD B systemwas used for X-ray diffractionmeasurements
Table 1 Values of 119889-spacing for various systems studied
System Peak positionlowast(2120579) 119889-spacing
MMT 1165 75839CPMMT 1130 78266PEOCPMMTSalt (21 wt) 2295 38720PEOPCPMMTSalt (21 wt) 2285 38090lowastPeak with highest intensity
The tensile properties of the samples were tested usingTestometric universal testing machine M350500 manufac-tured by Testometric UK The films of pure polymers andthat of selected compositions of composites with uniformthickness (measuredwith digitalmicrometer) andwidthwerecut for analysis The length of each sample was 50mm Theanalysis was performed at room temperature with cross-headspeed of 5mmmin For high accuracy and precision a sen-sitive load cell of 100 kg capacities with 10mg load detectionwith a minimum 001mm cross-head speed was used Aspecial griping system was designed for thin film griping toavoid any slippage during tensile test Standard procedure andformulae were used for calculating various tensile propertiesincluding Young modulus (stiffness) and elongation at breakData directly feed into computer interfaced with the UTM
The impedance measurements were carried out at roomtemperature (15∘C) using Solartron 1260 frequency responseanalyzer (FRA) over the frequency range of 1minus1times107 Hz and100mv voltage The impedance data were then transferred tothe (Z-plotZ-view) software package
3 Results and Discussion
Montmorillonite clay (MMT) clay structure along with CPCstructure is shown in Figure 1 The structure shows thatan octahedrally coordinated alumina is sandwiched betweentwo tetrahedrally coordinated silica The spacing betweenclay layers ranges in nanometers and in between theselayers water molecules and exchangeable cations like Na+ arepresent These +Ve ions are mostly near the layers where theminusVe site of the layer is present and a kind of attachmentis there between these The CPC has a bulky cationic headand hydrocarbon chain which is neutral The MMT claywas modified with cetylpyridinium chloride (CPC) whosestructure is shown in Figure 2 The mechanism clearly showsthat smaller Na+ is exchanged with the bulky cationic headgroup of CPC while NaCl is coming out after treatmentDue to this exchange and insertion of larger cation inbetween layers the interlayer spacing increases (see Table 1)The modified clay that is CPMMT is organophilic with alower surface energy which is more compatible with organicpolymers
31 X-Ray Diffraction Analysis of PEOLiClO4(Constant)
CPMMT Composite System XRD of pure PEO shows max-imum diffraction peaks representing highly crystalline struc-ture as already published in our earlier studies [13] LiClO
4
International Journal of Polymer Science 3
H2O H2O H2O
H2O H2O H2O
Clminus
+ + +CH3
AluminumOxygenSilicon
Tetrahedral
TetrahedralOctahedral
Water andexchangeablecations
Cetylpyridinium chloride(CPC) is a surfactant usedfor organic modification
N+
Figure 1 Structure of MMT clay and CPC
NaCl
MMTCPC
CPMMT
Na+Na+ Na+ Clminus
CH3
N+
N+
N+
N+
N+
N+
N+
N+
N+
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
Na+ ClminusNa+
Figure 2 Mechanism of modification of MMT
XRDwas not done but as reported in literature XRD patternof LiClO
4shows intense peaks at angle 2120579 = 18360 2320
2750 32990 and 36580 revealing the crystalline nature ofthe ionic salt [14] Figures 3 and 4 display the XRD scan ofpure and CPC modified MMT respectively It is clear fromthe diffractogram and Table 1 that modification of clay byCPC enhances the d-value from 75839 to 782366 by shifting2120579 value from 1165 to 1130 It also shows the addition ofnew peaks at 2120579 = 1775 and 553 and vanishing of somepeaks at 2120579 = 208 424 5015 and 543 The addition and
disappearance of peaks and alteration of d-values clearlydepict the successful modification of montmorillonite byCPC The rest of the peaks are not altered The increasingd-spacing will cause the dissociation of MMT resulting incomposites with better dispersion of clay particles [15]
The polymersaltCPC modified structure and interac-tion mechanism is given in Figure 5 The interaction ofCPMMTwith polymer (PEO) shows that polymer moleculescome in between the CPC layers attached to clay An elabo-ration of the intercalating portion clearly shows that there is
4 International Journal of Polymer Science
0
500
1000
1500
2000
2500
0 10 20 30 40 50 60 70
Inte
nsity
(CPS
)
Pure MMTd-valueCPS
100398816398807589391272116544912711571975426686105820803354381592265525721557434852129973884240
199184124550181747303501516879529354301503173106165
2120579
2120579 (∘)
Figure 3 XRD scan of pure MMT
CPC modified MMT
9983272051885782366138311304992571303177544912712001975338419160126602572155803485199387523454516597730555301498793146185
0 10 20 30 40 50 60 700
500
1000
1500
2000
2500
Inte
nsity
(CPS
)
d-valueCPS2120579
2120579 (∘)
Figure 4 XRD scan of CPMMT
increase in gallery spacing which is associated with loweringin surface energy Polymer intercalates within the galleriesas a result of the negative surface charge and the cationichead groups of CPC preferentially reside on the layer surfaceThe salt that is LiClO
4has also interactions with both the
polymer and the negatively charged clay layersComposites of PEOLiClO
4CPMMT were synthesized
with 198 33 462 and 594wt of modified montmoril-lonite loading keeping the mole fraction of salt constantat 35 wt The diffraction patterns of PEOSaltCPMMT(198 (A) 33 (B) 462 (C) and 594 (D) wt) compositesystems are shown in Figure 6 It can be revealed from theseXRD patterns that the PEO has the minimum crystallinitywhen the CPMMT loading is 33 wt This 33 wt ofCPMMT loading was selected as an optimum condition forthe synthesis of the composites The substantial increase inthe intensities of the XRD peaks on increasing CPMMTloadings suggests that the dispersion is better at lower clayloading than at higher loadings This is because the lithiumcation coordinates with the flexible CH
2-O- chain of PEO
forming complexes and thereby disturbing the crystallinityWhen the clay is loaded into the PEOLi ClO
4electrolyte
the crystallinity initially decreases up to 33 wt of clayloading and increases thereafter In case of undoped PEOthe crystallinity gradually decreases with an increase in clayloading because of the steric hindrance caused by the hugesurface area of randomly oriented clay throughout thematrixThe different crystallization behaviors of PEOLiClO
4clay
composite electrolyte and PEOClay composite is explainedby considering the fact that negatively charged clay layers
also coordinate with the lithium cation due to a strongelectrostatic interaction The interaction depends on theexpansion of silicate layers and clay content Because of thisinteraction PEO to Li+ interactions decrease and crystallinityincreases Thus two competing effects are present in thePEOLiClO
4Clay composite electrolyte one reduces the
crystallinity and the other favors the crystallinity At low clayloading the first factor predominates leading to a decrease inthe crystallinity and beyond the optimumclay concentrationsthe second factor predominates over the first resulting inhigher crystallinity [16 17] The presence of the CPMMThowever had no effect on the location of the peaks whichindicates that perfect exfoliation of the clay layer structureof the organoclay in PEO does not occur [18] The XRDpatterns of the fabricated composites show that most of thepeaks corresponding to pure LiClO
4have disappeared in the
composite system which reveals the dissolution of the saltin the polymer matrix Similarly the appearance of some ofthe peaks of the LiClO
4in the composite system confirms the
complexation of the salt with the polymer matrix
32 X-Ray Diffraction Analysis of PEOLiClO4(Variable)
CPMMT(33 wt) Composite System X-ray diffraction anal-ysis of PEOLiClO
4CPMMT composite with 33 wt of
CPMMT clay at varying concentrations of salt is shown inFigure 7 which depicts that PEOLiClO
4clay composites
first show decrease in crystallinity of PEOwith the increasingamount of salt but when the concentration of salt is increasedfrom PCS2 that is 35 wt the crystalline character of PEOstarts increasing this is attributed to the local aggregationof inorganic particles at higher salt concentration The sameresult ismanifested by ourmechanical and Scanning ElectronMicroscopy (SEM) studies
33 X-Ray Diffraction Analysis of PEOPMMALiClO4(Vari-
able)CPMMT(33 wt) BlendComposite System In order toinvestigate the effect of poly(methyl methacrylate) (PMMA)addition on the crystallinity of PEO in the blend compositeof PEOPMMALiClO
4CPMMT having variable concentra-
tions of salt and constant clay content (of 33 wt) X-rayanalysis was carried out From the diffractogram patterngiven in Figure 8 it is clear that though PMMA is amorphousin nature its addition to the composite system has no sig-nificant effect on the system The crystalline fraction of PEOincreased a little bit by its additionThis is because the amountof PEO in PEOPMMA blend is far more than overlap weightfraction (119882lowast) which causes PEO to crystallize and alsobecause PMMA interaction with CPMMT is more than thatof PEO which affects the properties of PEO when present inblendThe d-spacing between the layers of the system is foundto be decreasing (Table 1) which also accounts for increaseof crystalline behavior This result is consistent with our ACimpedance study and is also supported by the literature [18]
34 Ionic Conductivity of PEO Composite and Blend Compos-ite System In a Nyquist impedance plot the real part (119885) ofthe impedance was plotted against the imaginary part (119885)for data collected at frequencies ranging from 1 to 107Hz
International Journal of Polymer Science 5
OO
OO
OO
O
O
O
OO
O
O
OO
OO
OO
O
O
O
OO
O
O
OO
O
O
OO
OO
O
O
OO
O
O
OO
OO
O
O
OO
OO
O
O
OO
O
O
OO
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+N
+
N+
N+
N+
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+
N+
N+
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+N
+
N+
N+
N+
CH3 CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3 CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3 CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3CH3
CH3
CH3CH3CH3CH3
CPMMT Polymer
O O O
O
O O OO
O
O
O O
O
O
OO
OOO
O
OOOO
O
O
OO
O
O
OO
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
N+
N+
N+
CH3 CH3
CH3CH3
LiCIO4
OOO
O
OOOO
O
O
OO
O
O
OO
O O O
O
O O OO
O
O
O O
O
O
OO
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3 N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3 N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N
+
CH3N
+
CH3N
+
CH3N
+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N
+
CH3N
+
CH3N
+
CH3N
+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
Li+
CIO4minus
NN+
NN+
CH3
NN+
3
NNNNNN
CHC 3
NNN
CHC 3
CHC 3 NNN+
CH3
NNN+
CH3
NNN+
CH3
NNN+
CH3
NN+
CH3
NN+
CH3
NN+
CH3
NN+
CH3
NNN++
CH3
NNN++
CH3
NNN++
CH3
NNN++
CH3
NNN+
CHC 3
NNN+
CHC 3
NNN+
CHC 3
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
Figure 5 Mechanism of PEO-SaltCPMMT interaction
To investigate complete picture of the system an equivalentcircuit was used [19]The bulk resistance of the solid polymerelectrolyte (SPE) was consequent from the equivalent circuitFigures 9(a) 9(b) 9(c) and 9(d) show theNyquist impedanceplots for PEOLiClO
4 denoted as PS (a) PEOLiClO
4
after fitting to equivalent circuit (b) PEOCPMMTLiClO4
denoted as PCS (c) PEOPMMACPMMTLiClO4denoted
as PPCS (d) and impedance plot after fitting to the equiv-alent circuit respectively These diagrams deviate from anideal impedance spectrum that usually exhibits a standardsemicircle at the high frequency section and a vertical lineat a lower frequency section The deformed semicircle andthe inclined line for the polymeric filmelectrode systemmay be attributed to the irregular thickness and morphologyof the polymeric film and the roughness of the electrodesurface [20 21] To investigate the phenomenon a ldquoconstantphase elementrdquo (CPE) was employed in the equivalent circuitThe high frequency semicircle depicts the combination ofR1 and CPE-1 while the spike showing the trend for second
semicircle due to double layer capacitance (at the interface ofsolid polymer electrolyte and electrode) is reflected by CPE-2 [19] The equivalent circuit used for fitting data and tablefor parameters for the circuit elements evaluated by fittingthe impedance data for composite and blend system at roomtemperature (15∘C) is given in Figure 9 as inset
From equivalent circuits the bulk resistance values wereobtained The bulk resistance allows us to obtain the ionicconductivity using
120590 =
119868
119877119860
(1)
where 120590 = conductivity (Scm) 119877 = resistance (Ω) 119868 =thickness (cm) and 119860 = area of the electrode (cm2)
The capacitance values were calculated according to120596max119877119862=1 (2)
where 120596max corresponds to the frequency at the maximum ofsemicircle The capacitance values obtained for the bulk arein complete harmony with the earlier reported values [22]
6 International Journal of Polymer Science
(A)
(B)
(C)
(D)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 6 Combined XRD pattern of PEOSalt composite systemwith 198 (A) 33 (B) 462 (C) and 594 (D) wt of CPMMT
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 7 Combined XRD scans of PEOCPMMTSalt (PCS1)(21 wt A) PEOCPMMTSalt (PCS2) (35 wt B) and PEOCPMMTSalt (PCS3) (5 wt C)
The value of ionic conductivity obtained at room tem-perature (15∘C) for pure poly(ethylene oxide) (PEO) is lessthan 678 times 10minus10 S cmminus1 reported in the literature earlier byKumar and coworker [17] for the samemolecular weight PEOat 30∘C This difference in conductivity values is because ofthe temperature and changing nature of solvent used in ourstudy [23] From the table given as inset in Figure 10 it isclear that the conductivity of PEO at laboratory temperaturethat is 15∘C increases sharplywith the salt incorporationThe
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 8 Combined XRD scans of PEOPMMACPMMTSalt(PPCS1) (21 wt A) PEOPMMACPMMTSalt (PPCS2) (35 wtB) and PEOPMMACPMMTSalt (PPCS3) (5 wt C)
same trend in conductivity of PEO based electrolytes withthe salt concentration has also been observed by Srivastavaand Ibrahim et al [24 25] This increase is due to theincrease in charge carriers caused by the addition of higherconcentration of LiClO
4and the increase in the fraction of
amorphous phaseThe addition of ionic salt decreases degra-dation temperature because of the growth of amorphous frac-tion and destabilizes the polymer network The PEOLiClO
4
electrolyte with high salt concentration was found to be lessstable Alternatively CPMMT was used to overcome thesedrawbacks Inorganic fillers are usually used to improvethe electrochemical and mechanical properties [26] Clay isinorganic filler with intercalation property where clay layersmaintain their registry Intercalating polymer (residing poly-mer chains between silicates) in a layered clay host can pro-duce huge interfacial area to sustain the mechanical propertyof polymer electrolyte system and impart salt solvating powerto dissolve the lithium salt [27] A glance at Figure 10 and insettable reveals that the addition of salt at constant (33 wt)clay content increases the conductivity of PEOSaltCPMMT(PCS) composites retaining dimensional stability till PCS2(35 wt) beyond PCS2 further addition of salt decreases theconductivity badlyThis initial increase is due to the decreasein the crystallinity and increase in amorphous fraction ofPEO for ion conduction till equilibrium is achieved at PCS2This is consistent with our XRD results The conductivitydecreases drastically when amount of salt increases fromPCS2 to PCS3 (5wt) but is still higher than that of pristinepolymer The possible explanation for this behavior may beion association and the formation of charge multipliers [25]In order to study the effect of poly(methyl methacrylate)(PMMA) incorporation on the ionic conductivity of PEObased solid polymer electrolytes PMMA was blended with
International Journal of Polymer Science 7
1e6 2e6 3e6 4e600
minus1e6
minus2e6
minus3e6
minus4e6
Z998400
PEOLiClO4
N998400998400
(a)
Samples PS PCS PPCS661410 169520
CPE1-TCPE1-P 0922 09848 0535CPE2-TCPE2-P 0864 0715 08156
50000 100000 15000000
minus50000
minus100000
minus150000
Z998400
R1Ω 127 times 106
965 times 10minus11
544 times 10minus11
622 times 10minus11
946 times 10minus9
882 times 10minus9
877 times 10minus10
CPE1CPE2 CPE2R1
N998400998400
(b)
1e6 2e6 3e6 5e64e60
Z998400
0
minus1e6
minus2e6
minus3e6
minus5e6
minus4e6
PEOCPMMTLiClO4
N998400998400
(c)
1e7 2e7 3e70
Z998400
0
minus1e7
minus2e7
minus3e7PEOPMMACPMMTLiClO4
N998400998400
(d)
Figure 9 Typical Nyquist impedance plots for PEOSalt (PS) (a) PEOSalt (PS) after fitting to equivalent circuit (b) Inset showing thatdiagram of circuit and extracted parameters for the circuit elements of PS PCS and PPCS are summarized in the table PEOSaltCPMMT(PCS) (c) PEOPMMASaltCPMMT (PPCS) (d)
PEO for solid polymer electrolyte (SPE) composites Fromthe values of ionic conductivity given in Figure 10 and insettable it is clear that the addition of PMMA to PEOSaltelectrolyte system decreases the conductivity of PCS systembut still shows higher value than pure PEO films The rigidstructure of PMMA due to the entrapped silicate layersalters the segmental dynamics of PEO so there is decreasein conductivity Jeddi and coworkers [28] have reported anoverlapweight fraction for PEOPMMAblendwhich is about28 wt for PEO Overlap weight fraction is that weight atwhich PEO starts interpenetration and miscibility of blendsis affected In our system the amount of PEO is far more thanoverlap weight fraction So it causes decrease in conductivityand an increase in the agglomeration of clay by decreasing itsinteraction with the PEOThe same trend has been observed
in mechanical properties of the PEOPMMASaltCPMMT(PPCS) composites The values of ionic conductivity wereached at laboratory temperature of 15∘C are higher thanthose reported for the PEOPMMAsaltNa-MMT in theliterature at 25∘C [22] This increase may be caused by thebetter dispersion of CPMMT
35 Elongation at Break of PEOLiClO4CPMMT Composite
System Elongation at break is the strain at failure or percentchange at failure and explains the ductility of the materialwith external forceThe effect of salt addition on the ductilityor elongation is shown in Figure 11 The result fromFigure 11 depicts that ductility of the composite materialincreases with increasing salt concentration in the resultingcomposites This increase is attributed to the presence of
8 International Journal of Polymer Science
0 1 2 3 4 5 6
PPSCPSC
Salt concentration (wt)
Film codeP0PCPCS1PCS2PCS3PPCS1PPCS2PPCS3
minus1
minus7
minus8
minus9
minus10
minus11
minus12
726 times 10minus12
1017 times 10minus7
5 times 10minus10
294 times 10minus8
556 times 10minus11
220 times 10minus10
424 times 10minus9
331 times 10minus9
Bulk 120590 (Scm)
Log120590
(S cm
minus1)
Figure 10 Bulk ionic conductivity variation for PSC and PPSCwithweight of salt for composite system at room temperature (15∘C)
0
100
200
300
400
500
600
0
5
10
15
20
25
0 1 2 3 4 5 6Salt concentration (wt)
minus1
Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
clay)
syste
m
and
(PEO
+PM
MA+
clay)
PEO + clay
PEO + PMMA
PEO + PMMA + clay Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
PMM
A)
Figure 11 Variation of elongation at break for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
CPMMT which enhances the mobility of the PEO polymerThe highest elongation at break is obtained for the PCS2composite and beyond PCS2 elongation at break decreasesThe higher uniformity in the dispersion of salt and claywithin PEO is correlated with better adhesion between thecomponents of the composite due to the homogeneousdispersion of CPCMMT at PCS2 composition The decreasein the ductility beyond PCS2 is due to the restriction inchain mobility of the matrix and the filler particles acting asdefect points [29] This also shows that beyond certain limitof salt concentration the behavior changes Further at higher
20
40
60
80
100
120
140
160
0
200
400
600
800
1000
0 1 2 3 4 5 6Salt concentration (wt)
PEO + clay
PEO + PMMA
PEO + PMMA + clay
minus1
s mod
ulus
(Nm
m2) f
or (P
EO+
clay)
syste
mYo
ungrsquo
s mod
ulus
(Nm
m2)
and
(PEO
+PM
MA+
clay)
for (
PEO+
PMM
A)
Youn
grsquo
Figure 12 Variations of Youngrsquos modulus for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
concentrations the polymers exist in agglomeration and theclay is not well dispersed The overall result is the increasein the ductility of the composite material with increasingsalt concentration The net increase in elongation at breakfor PCS system suggests filler induced dimensional stabilityto the composite electrolyte films making them capable ofsustaining and withstanding any external pressureshock to abetter level
36 Youngrsquos Modulus of PEOLiClO4CPMMT Composites
Youngrsquos modulus is a variable that describes the relationshipof stress to strain within the elastic region This is measuredfrom the slope of the curve within the elastic area of thespecimen The modulus of elasticity describes a materialrsquosstiffness the greater the modulus the stiffer the material Itquantifies the elasticity of the polymerIt is truly associatedwith primary and secondary chemical bonds Unlike the neatpolymer where the mechanical properties are determinedalmost entirely by matrix the mechanical properties of thecomposite depend on the interaction between the polymerand the added fillers From Figure 12 it is clear that Youngrsquosmodulus of the composites electrolyte decreases with theincreasing concentration of inorganic contents at constantclay levelThe influence of LiClO
4on the mechanical proper-
ties of PEOCPMMT film resembles the plasticization effectThe interaction between PEO and CPMMT is weakened bythe increasing content of salt The same behavior of Youngrsquosmodulus with filler has been reported earlier in the literature[29] As mechanical properties change by changing thecomposition of components as well as with the applied forcethey are difficult to analyze Also this decrease may probablybe explained in terms of debonding around polymer andclay interphases and void formation It can be concluded thatvalue of modulus depends highly on the distribution of fillerparticles in the polymer matrix which in turn depends on
International Journal of Polymer Science 9
the particleparticle interaction (agglomeration) andpolymerparticle interaction (adhesion and wetting) and morphologyof the filler particles [30]
37 Elongations at Break of PEOPMMALiClO4CPMMTBlend Composites System In order to have a more clear ideaof the change inmechanical properties of the blend compositesystem first the addition of salt to the blend system wasstudied for its effect on the mechanical properties and thenCPMMT was added to the same system and the sampleswere analyzed by UTM From the results given in Figure 11it is clear that elongation at break decreases initially withthe increasing concentration of salt to the blend system andthen starts increasing with higher salt concentration Thisdecrease in failure strain is due to the rigid filler additionwhich restricts the mobility of the PEO polymermolecules toflow freely past one another thus causing premature failureThe original elasticity of PEO is distorted due to the additionof PMMA and LiClO
4which is in close agreement with the
conclusion that the addition of rigid particles like PMMAinto the polymer matrix increases its stiffness and toughness[31 32] Compositeswith these properties can be used for heatresistant materials or product packaging materials
38 Youngrsquos Modulus of PEOPMMALiClO4CPMM Blend
Composites System Youngrsquos modulus of the PEOPMMA asa function of salt is shown in Figure 12 From this Figure itis clear that Youngrsquos modulus of the blend composite showsan overall decrease with the addition of salt This decreaseshows the weaker PEO interchain interaction and increasein the particle size of the inorganic phase because of localaggregations of particles in the presence of PMMA thesephenomenamay act as flaws in it [33 34]The same trend hasbeen confirmed by the SEM result as well This means thatthe addition of salt to the PEOPMMA composite suppressesthematerialrsquos stiffness and hence elasticity of the polymer Butwhen clay was added to the same PEOPMMASalt systeman enormous increase in the value of Young modulus wasobserved as shown in Figure 12 This is due to the interca-lation of polymer chains within the clay galleries that avoidsegmental motion of the polymer chains [35] Although thereis an overall decrease in the value of Young modulus of thePEOPMMALiClO
4CPMMT system with increasing salt
concentration still it is much higher than that of the virgin(neat) poly(ethylene oxide) (PEO) and PEOSaltCPMMTThis is in close agreement with the conclusion that theaddition of rigid particles like PMMA into the polymermatrix increases its stiffness [31]
4 Conclusions
This work used cetylpyridinium chloride to modify MMTmixed with higher molecular weight PEOLiClO
4and
PEOPMMALiClO4to produce composite materials The
experimental results showed that at constant salt contentthe addition of CPMMT first reduces crystallinity of PEOtill 33 wt of clay and then starts increasing at higher claycontent Thus 33 wt of clay was selected as the optimum
clay loadings for composites fabrication The XRD resultsshowed that the crystallinity of composites at optimum clayloading increases with increasing salt content and ionicconductivity obtained from impedance technique showeddeclining trend with higher salt content The addition of50wt of higher molecular weight PMMA to the com-posite of PEOSaltCPMMT affected the properties due tothe immiscibility or aggregation of filler within the poly-mer matrix however the blend composites showed bettermechanical performanceThe composite of PEOwith 35 wtof salt and 33 wt of CPMMT exhibited better performance
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] S Sultana Fabrication and studies on thin film composites ofPoly (Ethylene Oxide) [PhD thesis] University of PeshawarPeshawar Pakistan 2013
[2] T Lan P D Kaviratna and T J Pinnavaia ldquoEpoxy self-polymerization in smectite claysrdquo Journal of Physics and Chem-istry of Solids vol 57 no 6-8 pp 1005ndash1010 1996
[3] X Q Yang H S Lee L Hanson J McBreen and Y OkamotoldquoDevelopment of a new plasticizer for poly(ethylene oxide)-based polymer electrolyte and the investigation of their ion-pairdissociation effectrdquo Journal of Power Sources vol 54 no 2 pp198ndash204 1995
[4] R Mishra and K J Rao ldquoElectrical conductivity studies ofpoly(ethyleneoxide)-poly(vinylalcohol) blendsrdquo Solid State Ion-ics vol 106 no 1-2 pp 113ndash127 1998
[5] M S Khan A Shakoor and J Nisar ldquoConductance study ofpoly(ethylene oxide)- and poly(propylene oxide)-based poly-electrolytesrdquo Ionics vol 16 no 6 pp 539ndash542 2010
[6] Z Shen G P Simon and Y-B Cheng ldquoComparison ofsolution intercalation and melt intercalation of polymer-claynanocompositesrdquo Polymer vol 43 no 15 pp 4251ndash4260 2002
[7] P Aranda and E Ruiz-Hitzky ldquoNew polyelectrolyte materialsbased on smectite polyoxyethylene intercalation compoundsrdquoActa Polymerica vol 45 no 2 pp 59ndash67 1994
[8] D Ratna S Divekar A B Samui B C Chakraborty and AK Banthia ldquoPoly(ethylene oxide)clay nanocomposite thermo-mechanical properties andmorphologyrdquo Polymer vol 47 no 11pp 4068ndash4074 2006
[9] D Ratna S Divekar S Patchaiappan A B Samui and BC Chakraborty ldquoPoly(ethylene oxide)clay nanocomposites forsolid polymer electrolyte applicationsrdquo Polymer Internationalvol 56 no 7 pp 900ndash904 2007
[10] S K Lim JW Kim I Chin Y K Kwon andH J Choi ldquoPrepa-ration and interaction characteristics of organically modifiedmontmorillonite nanocomposite with miscible polymer blendof poly(ethylene oxide) and poly(methyl methacrylate)rdquo Chem-istry of Materials vol 14 no 5 pp 1989ndash1994 2002
[11] Y H Hyun S T Lim H J Choi and M S Jhon ldquoRheologyof poly(ethylene oxide)organoclay nanocompositesrdquo Macro-molecules vol 34 no 23 pp 8084ndash8093 2001
10 International Journal of Polymer Science
[12] H-W Chen C-Y Chiu and F-C Chang ldquoConductivity en-hancement mechanism of the poly(ethylene oxide)modified-clayLiClO
4systemsrdquo Journal of Polymer Science Part B Poly-
mer Physics vol 40 no 13 pp 1342ndash1353 2002[13] S Sultana M S Khan and M Humayun ldquoPreparation mor-
phology and thermal and optical properties of thin films offerric chloridepolyethylene oxide compositesrdquo Turkish Journalof Chemistry vol 36 no 5 pp 709ndash716 2012
[14] R Baskaran S Selvasekarapandian N Kuwata J Kawamuraand T Hattori ldquoConductivity and thermal studies of blendpolymer electrolytes based on PVAc-PMMArdquo Solid State Ionicsvol 177 no 26-32 pp 2679ndash2682 2006
[15] S K Lim S T Lim H B Kim I Chin and H J Choi ldquoPrepa-ration and physical characterization of polyepichlorohydrinelastomerclay nanocompositesrdquo Journal of MacromolecularScience Part B Physics vol 42 no 6 pp 1197ndash1208 2003
[16] B Chen and J R G Evans ldquoPreferential intercalation inpolymer-clay nanocompositesrdquo Journal of Physical Chemistry Bvol 108 no 39 pp 14986ndash14990 2004
[17] B Kumar and L G Scanlon ldquoPolymer-ceramic compositeelectrolytes conductivity and thermal history effectsrdquo SolidState Ionics vol 124 no 3 pp 239ndash254 1999
[18] J-H Chang S J Kim Y L Joo and S Im ldquoPoly(ethyleneterephthalate) nanocomposites by in situ interlayer polymeriza-tion the thermo-mechanical properties and morphology of thehybrid fibersrdquo Polymer vol 45 no 3 pp 919ndash926 2004
[19] X Qian N Gu Z Cheng X Yang E Wang and S DongldquoImpedance study of (PEO)
10LiClO
4-Al2O3composite polymer
electrolyte with blocking electrodesrdquo Electrochimica Acta vol46 no 12 pp 1829ndash1836 2001
[20] G J Brug A L G Van den Eeden M Sluyters-Rehbach and JH Sluyters ldquoThe analysis of electrode impedances complicatedby the presence of a constant phase elementrdquo Journal ofElectroanalytical Chemistry and Interfacial Electrochemistry vol176 no 1-2 pp 275ndash295 1984
[21] F Bellucci M Valentino T Monetta et al ldquoImpedance spec-troscopy of reactive polymers 1rdquo Journal of Polymer SciencePart B Polymer Physics vol 32 no 15 pp 2519ndash2527 1994
[22] J T S Irvine D C Sinclair and A R West ldquoElectroceramicscharacterization by impedance spectroscopyrdquo Advanced Mate-rials vol 2 no 3 pp 132ndash138 1990
[23] K V Kumar and G S Sundari ldquoConductivity studies of(PEO +KHCO
3) solid electrolyte system and its application
as an electrochemical cellrdquo Journal of Engineering Science andTechnology vol 5 no 2 pp 130ndash139 2010
[24] P C Srivastava in Solid State Ionics Materials and ApplicationsB V R Chowdar Ed pp 561ndash565 World Scientific Singapore1992
[25] S Ibrahim and M R Johan ldquoConductivity thermal andneural networkmodel nanocomposite solid polymer electrolytesystem (PEO-LiPF6-EC-CNT)rdquo International Journal of Elec-trochemical Science vol 6 no 11 pp 5565ndash5587 2011
[26] P P Chu M J Reddy and J Tsai ldquoStructural and transportcharacteristics of polyethylene oxidephenolic resin blend solidpolymer electrolytesrdquo Journal of Polymer Science Part B Poly-mer Physics vol 42 no 21 pp 3866ndash3875 2004
[27] H-W Chen C-Y Chiu and F-C Chang ldquoConductivityenhancement mechanism of the poly(ethylene oxide)modi-fied-clayLiClO
4systemsrdquo Journal of Polymer Science Part B
Polymer Physics vol 40 no 13 pp 1342ndash1353 2002
[28] K Jeddi N T Qazvini S H Jafari and H A KhonakdarldquoEnhanced ionic conductivity in PEOPMMA glassy misci-ble blends role of nano-confinement of minority componentchainsrdquo Journal of Polymer Science Part B Polymer Physics vol48 no 19 pp 2065ndash2071 2010
[29] S Ramesh and N B Khoo ldquoConductivity mechanical andthermal studies on poly(methyl methacrylate)-based polymerelectrolytes complexed with lithium tetraborate and propylenecarbonaterdquo Journal of Materials Engineering and Performancevol 21 no 1 pp 89ndash94 2012
[30] F Ali Synthesis and characterization of polyimidesilicabased nano-composites material [MPhil Thesis] University ofPeshawar Peshawar Pakistan 2006
[31] S Bai J Chen Z Huang and Z Yu ldquoThe role of the interfacialstrength in glass bead filled HDPErdquo Journal of Materials ScienceLetters vol 19 no 17 pp 1587ndash1589 2000
[32] G Nasar Synthesis and characterization of poly (vinyl alcohol)composites [MPhil thesis] University of Peshawar PeshawarPakistan 2008
[33] A Bandyopadhyay M de Sarkar and A K BhowmickldquoPoly(vinyl alcohol)silica hybrid nanocomposites by sol-geltechnique synthesis and propertiesrdquo Journal of Materials Sci-ence vol 40 no 19 pp 5233ndash5241 2005
[34] H B Kim J S Choi C H Lee S T Lim M S Jhon andH J Choi ldquoPolymer blendorganoclay nanocomposite withpoly(ethylene oxide) and poly(methylmethacrylate)rdquo EuropeanPolymer Journal vol 41 no 4 pp 679ndash685 2005
[35] R L Ledoux and J L White ldquoInfra red studies of hydrogenbonding interaction between kaolinite surfaces and intercalatedpotassium acetate hydrazine formamide and ureardquo Journal ofColloid and Interface Science vol 21 pp 27ndash52 1996
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
International Journal of Polymer Science 3
H2O H2O H2O
H2O H2O H2O
Clminus
+ + +CH3
AluminumOxygenSilicon
Tetrahedral
TetrahedralOctahedral
Water andexchangeablecations
Cetylpyridinium chloride(CPC) is a surfactant usedfor organic modification
N+
Figure 1 Structure of MMT clay and CPC
NaCl
MMTCPC
CPMMT
Na+Na+ Na+ Clminus
CH3
N+
N+
N+
N+
N+
N+
N+
N+
N+
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
Na+ ClminusNa+
Figure 2 Mechanism of modification of MMT
XRDwas not done but as reported in literature XRD patternof LiClO
4shows intense peaks at angle 2120579 = 18360 2320
2750 32990 and 36580 revealing the crystalline nature ofthe ionic salt [14] Figures 3 and 4 display the XRD scan ofpure and CPC modified MMT respectively It is clear fromthe diffractogram and Table 1 that modification of clay byCPC enhances the d-value from 75839 to 782366 by shifting2120579 value from 1165 to 1130 It also shows the addition ofnew peaks at 2120579 = 1775 and 553 and vanishing of somepeaks at 2120579 = 208 424 5015 and 543 The addition and
disappearance of peaks and alteration of d-values clearlydepict the successful modification of montmorillonite byCPC The rest of the peaks are not altered The increasingd-spacing will cause the dissociation of MMT resulting incomposites with better dispersion of clay particles [15]
The polymersaltCPC modified structure and interac-tion mechanism is given in Figure 5 The interaction ofCPMMTwith polymer (PEO) shows that polymer moleculescome in between the CPC layers attached to clay An elabo-ration of the intercalating portion clearly shows that there is
4 International Journal of Polymer Science
0
500
1000
1500
2000
2500
0 10 20 30 40 50 60 70
Inte
nsity
(CPS
)
Pure MMTd-valueCPS
100398816398807589391272116544912711571975426686105820803354381592265525721557434852129973884240
199184124550181747303501516879529354301503173106165
2120579
2120579 (∘)
Figure 3 XRD scan of pure MMT
CPC modified MMT
9983272051885782366138311304992571303177544912712001975338419160126602572155803485199387523454516597730555301498793146185
0 10 20 30 40 50 60 700
500
1000
1500
2000
2500
Inte
nsity
(CPS
)
d-valueCPS2120579
2120579 (∘)
Figure 4 XRD scan of CPMMT
increase in gallery spacing which is associated with loweringin surface energy Polymer intercalates within the galleriesas a result of the negative surface charge and the cationichead groups of CPC preferentially reside on the layer surfaceThe salt that is LiClO
4has also interactions with both the
polymer and the negatively charged clay layersComposites of PEOLiClO
4CPMMT were synthesized
with 198 33 462 and 594wt of modified montmoril-lonite loading keeping the mole fraction of salt constantat 35 wt The diffraction patterns of PEOSaltCPMMT(198 (A) 33 (B) 462 (C) and 594 (D) wt) compositesystems are shown in Figure 6 It can be revealed from theseXRD patterns that the PEO has the minimum crystallinitywhen the CPMMT loading is 33 wt This 33 wt ofCPMMT loading was selected as an optimum condition forthe synthesis of the composites The substantial increase inthe intensities of the XRD peaks on increasing CPMMTloadings suggests that the dispersion is better at lower clayloading than at higher loadings This is because the lithiumcation coordinates with the flexible CH
2-O- chain of PEO
forming complexes and thereby disturbing the crystallinityWhen the clay is loaded into the PEOLi ClO
4electrolyte
the crystallinity initially decreases up to 33 wt of clayloading and increases thereafter In case of undoped PEOthe crystallinity gradually decreases with an increase in clayloading because of the steric hindrance caused by the hugesurface area of randomly oriented clay throughout thematrixThe different crystallization behaviors of PEOLiClO
4clay
composite electrolyte and PEOClay composite is explainedby considering the fact that negatively charged clay layers
also coordinate with the lithium cation due to a strongelectrostatic interaction The interaction depends on theexpansion of silicate layers and clay content Because of thisinteraction PEO to Li+ interactions decrease and crystallinityincreases Thus two competing effects are present in thePEOLiClO
4Clay composite electrolyte one reduces the
crystallinity and the other favors the crystallinity At low clayloading the first factor predominates leading to a decrease inthe crystallinity and beyond the optimumclay concentrationsthe second factor predominates over the first resulting inhigher crystallinity [16 17] The presence of the CPMMThowever had no effect on the location of the peaks whichindicates that perfect exfoliation of the clay layer structureof the organoclay in PEO does not occur [18] The XRDpatterns of the fabricated composites show that most of thepeaks corresponding to pure LiClO
4have disappeared in the
composite system which reveals the dissolution of the saltin the polymer matrix Similarly the appearance of some ofthe peaks of the LiClO
4in the composite system confirms the
complexation of the salt with the polymer matrix
32 X-Ray Diffraction Analysis of PEOLiClO4(Variable)
CPMMT(33 wt) Composite System X-ray diffraction anal-ysis of PEOLiClO
4CPMMT composite with 33 wt of
CPMMT clay at varying concentrations of salt is shown inFigure 7 which depicts that PEOLiClO
4clay composites
first show decrease in crystallinity of PEOwith the increasingamount of salt but when the concentration of salt is increasedfrom PCS2 that is 35 wt the crystalline character of PEOstarts increasing this is attributed to the local aggregationof inorganic particles at higher salt concentration The sameresult ismanifested by ourmechanical and Scanning ElectronMicroscopy (SEM) studies
33 X-Ray Diffraction Analysis of PEOPMMALiClO4(Vari-
able)CPMMT(33 wt) BlendComposite System In order toinvestigate the effect of poly(methyl methacrylate) (PMMA)addition on the crystallinity of PEO in the blend compositeof PEOPMMALiClO
4CPMMT having variable concentra-
tions of salt and constant clay content (of 33 wt) X-rayanalysis was carried out From the diffractogram patterngiven in Figure 8 it is clear that though PMMA is amorphousin nature its addition to the composite system has no sig-nificant effect on the system The crystalline fraction of PEOincreased a little bit by its additionThis is because the amountof PEO in PEOPMMA blend is far more than overlap weightfraction (119882lowast) which causes PEO to crystallize and alsobecause PMMA interaction with CPMMT is more than thatof PEO which affects the properties of PEO when present inblendThe d-spacing between the layers of the system is foundto be decreasing (Table 1) which also accounts for increaseof crystalline behavior This result is consistent with our ACimpedance study and is also supported by the literature [18]
34 Ionic Conductivity of PEO Composite and Blend Compos-ite System In a Nyquist impedance plot the real part (119885) ofthe impedance was plotted against the imaginary part (119885)for data collected at frequencies ranging from 1 to 107Hz
International Journal of Polymer Science 5
OO
OO
OO
O
O
O
OO
O
O
OO
OO
OO
O
O
O
OO
O
O
OO
O
O
OO
OO
O
O
OO
O
O
OO
OO
O
O
OO
OO
O
O
OO
O
O
OO
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+N
+
N+
N+
N+
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+
N+
N+
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+N
+
N+
N+
N+
CH3 CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3 CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3 CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3CH3
CH3
CH3CH3CH3CH3
CPMMT Polymer
O O O
O
O O OO
O
O
O O
O
O
OO
OOO
O
OOOO
O
O
OO
O
O
OO
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
N+
N+
N+
CH3 CH3
CH3CH3
LiCIO4
OOO
O
OOOO
O
O
OO
O
O
OO
O O O
O
O O OO
O
O
O O
O
O
OO
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3 N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3 N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N
+
CH3N
+
CH3N
+
CH3N
+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N
+
CH3N
+
CH3N
+
CH3N
+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
Li+
CIO4minus
NN+
NN+
CH3
NN+
3
NNNNNN
CHC 3
NNN
CHC 3
CHC 3 NNN+
CH3
NNN+
CH3
NNN+
CH3
NNN+
CH3
NN+
CH3
NN+
CH3
NN+
CH3
NN+
CH3
NNN++
CH3
NNN++
CH3
NNN++
CH3
NNN++
CH3
NNN+
CHC 3
NNN+
CHC 3
NNN+
CHC 3
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
Figure 5 Mechanism of PEO-SaltCPMMT interaction
To investigate complete picture of the system an equivalentcircuit was used [19]The bulk resistance of the solid polymerelectrolyte (SPE) was consequent from the equivalent circuitFigures 9(a) 9(b) 9(c) and 9(d) show theNyquist impedanceplots for PEOLiClO
4 denoted as PS (a) PEOLiClO
4
after fitting to equivalent circuit (b) PEOCPMMTLiClO4
denoted as PCS (c) PEOPMMACPMMTLiClO4denoted
as PPCS (d) and impedance plot after fitting to the equiv-alent circuit respectively These diagrams deviate from anideal impedance spectrum that usually exhibits a standardsemicircle at the high frequency section and a vertical lineat a lower frequency section The deformed semicircle andthe inclined line for the polymeric filmelectrode systemmay be attributed to the irregular thickness and morphologyof the polymeric film and the roughness of the electrodesurface [20 21] To investigate the phenomenon a ldquoconstantphase elementrdquo (CPE) was employed in the equivalent circuitThe high frequency semicircle depicts the combination ofR1 and CPE-1 while the spike showing the trend for second
semicircle due to double layer capacitance (at the interface ofsolid polymer electrolyte and electrode) is reflected by CPE-2 [19] The equivalent circuit used for fitting data and tablefor parameters for the circuit elements evaluated by fittingthe impedance data for composite and blend system at roomtemperature (15∘C) is given in Figure 9 as inset
From equivalent circuits the bulk resistance values wereobtained The bulk resistance allows us to obtain the ionicconductivity using
120590 =
119868
119877119860
(1)
where 120590 = conductivity (Scm) 119877 = resistance (Ω) 119868 =thickness (cm) and 119860 = area of the electrode (cm2)
The capacitance values were calculated according to120596max119877119862=1 (2)
where 120596max corresponds to the frequency at the maximum ofsemicircle The capacitance values obtained for the bulk arein complete harmony with the earlier reported values [22]
6 International Journal of Polymer Science
(A)
(B)
(C)
(D)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 6 Combined XRD pattern of PEOSalt composite systemwith 198 (A) 33 (B) 462 (C) and 594 (D) wt of CPMMT
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 7 Combined XRD scans of PEOCPMMTSalt (PCS1)(21 wt A) PEOCPMMTSalt (PCS2) (35 wt B) and PEOCPMMTSalt (PCS3) (5 wt C)
The value of ionic conductivity obtained at room tem-perature (15∘C) for pure poly(ethylene oxide) (PEO) is lessthan 678 times 10minus10 S cmminus1 reported in the literature earlier byKumar and coworker [17] for the samemolecular weight PEOat 30∘C This difference in conductivity values is because ofthe temperature and changing nature of solvent used in ourstudy [23] From the table given as inset in Figure 10 it isclear that the conductivity of PEO at laboratory temperaturethat is 15∘C increases sharplywith the salt incorporationThe
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 8 Combined XRD scans of PEOPMMACPMMTSalt(PPCS1) (21 wt A) PEOPMMACPMMTSalt (PPCS2) (35 wtB) and PEOPMMACPMMTSalt (PPCS3) (5 wt C)
same trend in conductivity of PEO based electrolytes withthe salt concentration has also been observed by Srivastavaand Ibrahim et al [24 25] This increase is due to theincrease in charge carriers caused by the addition of higherconcentration of LiClO
4and the increase in the fraction of
amorphous phaseThe addition of ionic salt decreases degra-dation temperature because of the growth of amorphous frac-tion and destabilizes the polymer network The PEOLiClO
4
electrolyte with high salt concentration was found to be lessstable Alternatively CPMMT was used to overcome thesedrawbacks Inorganic fillers are usually used to improvethe electrochemical and mechanical properties [26] Clay isinorganic filler with intercalation property where clay layersmaintain their registry Intercalating polymer (residing poly-mer chains between silicates) in a layered clay host can pro-duce huge interfacial area to sustain the mechanical propertyof polymer electrolyte system and impart salt solvating powerto dissolve the lithium salt [27] A glance at Figure 10 and insettable reveals that the addition of salt at constant (33 wt)clay content increases the conductivity of PEOSaltCPMMT(PCS) composites retaining dimensional stability till PCS2(35 wt) beyond PCS2 further addition of salt decreases theconductivity badlyThis initial increase is due to the decreasein the crystallinity and increase in amorphous fraction ofPEO for ion conduction till equilibrium is achieved at PCS2This is consistent with our XRD results The conductivitydecreases drastically when amount of salt increases fromPCS2 to PCS3 (5wt) but is still higher than that of pristinepolymer The possible explanation for this behavior may beion association and the formation of charge multipliers [25]In order to study the effect of poly(methyl methacrylate)(PMMA) incorporation on the ionic conductivity of PEObased solid polymer electrolytes PMMA was blended with
International Journal of Polymer Science 7
1e6 2e6 3e6 4e600
minus1e6
minus2e6
minus3e6
minus4e6
Z998400
PEOLiClO4
N998400998400
(a)
Samples PS PCS PPCS661410 169520
CPE1-TCPE1-P 0922 09848 0535CPE2-TCPE2-P 0864 0715 08156
50000 100000 15000000
minus50000
minus100000
minus150000
Z998400
R1Ω 127 times 106
965 times 10minus11
544 times 10minus11
622 times 10minus11
946 times 10minus9
882 times 10minus9
877 times 10minus10
CPE1CPE2 CPE2R1
N998400998400
(b)
1e6 2e6 3e6 5e64e60
Z998400
0
minus1e6
minus2e6
minus3e6
minus5e6
minus4e6
PEOCPMMTLiClO4
N998400998400
(c)
1e7 2e7 3e70
Z998400
0
minus1e7
minus2e7
minus3e7PEOPMMACPMMTLiClO4
N998400998400
(d)
Figure 9 Typical Nyquist impedance plots for PEOSalt (PS) (a) PEOSalt (PS) after fitting to equivalent circuit (b) Inset showing thatdiagram of circuit and extracted parameters for the circuit elements of PS PCS and PPCS are summarized in the table PEOSaltCPMMT(PCS) (c) PEOPMMASaltCPMMT (PPCS) (d)
PEO for solid polymer electrolyte (SPE) composites Fromthe values of ionic conductivity given in Figure 10 and insettable it is clear that the addition of PMMA to PEOSaltelectrolyte system decreases the conductivity of PCS systembut still shows higher value than pure PEO films The rigidstructure of PMMA due to the entrapped silicate layersalters the segmental dynamics of PEO so there is decreasein conductivity Jeddi and coworkers [28] have reported anoverlapweight fraction for PEOPMMAblendwhich is about28 wt for PEO Overlap weight fraction is that weight atwhich PEO starts interpenetration and miscibility of blendsis affected In our system the amount of PEO is far more thanoverlap weight fraction So it causes decrease in conductivityand an increase in the agglomeration of clay by decreasing itsinteraction with the PEOThe same trend has been observed
in mechanical properties of the PEOPMMASaltCPMMT(PPCS) composites The values of ionic conductivity wereached at laboratory temperature of 15∘C are higher thanthose reported for the PEOPMMAsaltNa-MMT in theliterature at 25∘C [22] This increase may be caused by thebetter dispersion of CPMMT
35 Elongation at Break of PEOLiClO4CPMMT Composite
System Elongation at break is the strain at failure or percentchange at failure and explains the ductility of the materialwith external forceThe effect of salt addition on the ductilityor elongation is shown in Figure 11 The result fromFigure 11 depicts that ductility of the composite materialincreases with increasing salt concentration in the resultingcomposites This increase is attributed to the presence of
8 International Journal of Polymer Science
0 1 2 3 4 5 6
PPSCPSC
Salt concentration (wt)
Film codeP0PCPCS1PCS2PCS3PPCS1PPCS2PPCS3
minus1
minus7
minus8
minus9
minus10
minus11
minus12
726 times 10minus12
1017 times 10minus7
5 times 10minus10
294 times 10minus8
556 times 10minus11
220 times 10minus10
424 times 10minus9
331 times 10minus9
Bulk 120590 (Scm)
Log120590
(S cm
minus1)
Figure 10 Bulk ionic conductivity variation for PSC and PPSCwithweight of salt for composite system at room temperature (15∘C)
0
100
200
300
400
500
600
0
5
10
15
20
25
0 1 2 3 4 5 6Salt concentration (wt)
minus1
Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
clay)
syste
m
and
(PEO
+PM
MA+
clay)
PEO + clay
PEO + PMMA
PEO + PMMA + clay Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
PMM
A)
Figure 11 Variation of elongation at break for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
CPMMT which enhances the mobility of the PEO polymerThe highest elongation at break is obtained for the PCS2composite and beyond PCS2 elongation at break decreasesThe higher uniformity in the dispersion of salt and claywithin PEO is correlated with better adhesion between thecomponents of the composite due to the homogeneousdispersion of CPCMMT at PCS2 composition The decreasein the ductility beyond PCS2 is due to the restriction inchain mobility of the matrix and the filler particles acting asdefect points [29] This also shows that beyond certain limitof salt concentration the behavior changes Further at higher
20
40
60
80
100
120
140
160
0
200
400
600
800
1000
0 1 2 3 4 5 6Salt concentration (wt)
PEO + clay
PEO + PMMA
PEO + PMMA + clay
minus1
s mod
ulus
(Nm
m2) f
or (P
EO+
clay)
syste
mYo
ungrsquo
s mod
ulus
(Nm
m2)
and
(PEO
+PM
MA+
clay)
for (
PEO+
PMM
A)
Youn
grsquo
Figure 12 Variations of Youngrsquos modulus for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
concentrations the polymers exist in agglomeration and theclay is not well dispersed The overall result is the increasein the ductility of the composite material with increasingsalt concentration The net increase in elongation at breakfor PCS system suggests filler induced dimensional stabilityto the composite electrolyte films making them capable ofsustaining and withstanding any external pressureshock to abetter level
36 Youngrsquos Modulus of PEOLiClO4CPMMT Composites
Youngrsquos modulus is a variable that describes the relationshipof stress to strain within the elastic region This is measuredfrom the slope of the curve within the elastic area of thespecimen The modulus of elasticity describes a materialrsquosstiffness the greater the modulus the stiffer the material Itquantifies the elasticity of the polymerIt is truly associatedwith primary and secondary chemical bonds Unlike the neatpolymer where the mechanical properties are determinedalmost entirely by matrix the mechanical properties of thecomposite depend on the interaction between the polymerand the added fillers From Figure 12 it is clear that Youngrsquosmodulus of the composites electrolyte decreases with theincreasing concentration of inorganic contents at constantclay levelThe influence of LiClO
4on the mechanical proper-
ties of PEOCPMMT film resembles the plasticization effectThe interaction between PEO and CPMMT is weakened bythe increasing content of salt The same behavior of Youngrsquosmodulus with filler has been reported earlier in the literature[29] As mechanical properties change by changing thecomposition of components as well as with the applied forcethey are difficult to analyze Also this decrease may probablybe explained in terms of debonding around polymer andclay interphases and void formation It can be concluded thatvalue of modulus depends highly on the distribution of fillerparticles in the polymer matrix which in turn depends on
International Journal of Polymer Science 9
the particleparticle interaction (agglomeration) andpolymerparticle interaction (adhesion and wetting) and morphologyof the filler particles [30]
37 Elongations at Break of PEOPMMALiClO4CPMMTBlend Composites System In order to have a more clear ideaof the change inmechanical properties of the blend compositesystem first the addition of salt to the blend system wasstudied for its effect on the mechanical properties and thenCPMMT was added to the same system and the sampleswere analyzed by UTM From the results given in Figure 11it is clear that elongation at break decreases initially withthe increasing concentration of salt to the blend system andthen starts increasing with higher salt concentration Thisdecrease in failure strain is due to the rigid filler additionwhich restricts the mobility of the PEO polymermolecules toflow freely past one another thus causing premature failureThe original elasticity of PEO is distorted due to the additionof PMMA and LiClO
4which is in close agreement with the
conclusion that the addition of rigid particles like PMMAinto the polymer matrix increases its stiffness and toughness[31 32] Compositeswith these properties can be used for heatresistant materials or product packaging materials
38 Youngrsquos Modulus of PEOPMMALiClO4CPMM Blend
Composites System Youngrsquos modulus of the PEOPMMA asa function of salt is shown in Figure 12 From this Figure itis clear that Youngrsquos modulus of the blend composite showsan overall decrease with the addition of salt This decreaseshows the weaker PEO interchain interaction and increasein the particle size of the inorganic phase because of localaggregations of particles in the presence of PMMA thesephenomenamay act as flaws in it [33 34]The same trend hasbeen confirmed by the SEM result as well This means thatthe addition of salt to the PEOPMMA composite suppressesthematerialrsquos stiffness and hence elasticity of the polymer Butwhen clay was added to the same PEOPMMASalt systeman enormous increase in the value of Young modulus wasobserved as shown in Figure 12 This is due to the interca-lation of polymer chains within the clay galleries that avoidsegmental motion of the polymer chains [35] Although thereis an overall decrease in the value of Young modulus of thePEOPMMALiClO
4CPMMT system with increasing salt
concentration still it is much higher than that of the virgin(neat) poly(ethylene oxide) (PEO) and PEOSaltCPMMTThis is in close agreement with the conclusion that theaddition of rigid particles like PMMA into the polymermatrix increases its stiffness [31]
4 Conclusions
This work used cetylpyridinium chloride to modify MMTmixed with higher molecular weight PEOLiClO
4and
PEOPMMALiClO4to produce composite materials The
experimental results showed that at constant salt contentthe addition of CPMMT first reduces crystallinity of PEOtill 33 wt of clay and then starts increasing at higher claycontent Thus 33 wt of clay was selected as the optimum
clay loadings for composites fabrication The XRD resultsshowed that the crystallinity of composites at optimum clayloading increases with increasing salt content and ionicconductivity obtained from impedance technique showeddeclining trend with higher salt content The addition of50wt of higher molecular weight PMMA to the com-posite of PEOSaltCPMMT affected the properties due tothe immiscibility or aggregation of filler within the poly-mer matrix however the blend composites showed bettermechanical performanceThe composite of PEOwith 35 wtof salt and 33 wt of CPMMT exhibited better performance
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] S Sultana Fabrication and studies on thin film composites ofPoly (Ethylene Oxide) [PhD thesis] University of PeshawarPeshawar Pakistan 2013
[2] T Lan P D Kaviratna and T J Pinnavaia ldquoEpoxy self-polymerization in smectite claysrdquo Journal of Physics and Chem-istry of Solids vol 57 no 6-8 pp 1005ndash1010 1996
[3] X Q Yang H S Lee L Hanson J McBreen and Y OkamotoldquoDevelopment of a new plasticizer for poly(ethylene oxide)-based polymer electrolyte and the investigation of their ion-pairdissociation effectrdquo Journal of Power Sources vol 54 no 2 pp198ndash204 1995
[4] R Mishra and K J Rao ldquoElectrical conductivity studies ofpoly(ethyleneoxide)-poly(vinylalcohol) blendsrdquo Solid State Ion-ics vol 106 no 1-2 pp 113ndash127 1998
[5] M S Khan A Shakoor and J Nisar ldquoConductance study ofpoly(ethylene oxide)- and poly(propylene oxide)-based poly-electrolytesrdquo Ionics vol 16 no 6 pp 539ndash542 2010
[6] Z Shen G P Simon and Y-B Cheng ldquoComparison ofsolution intercalation and melt intercalation of polymer-claynanocompositesrdquo Polymer vol 43 no 15 pp 4251ndash4260 2002
[7] P Aranda and E Ruiz-Hitzky ldquoNew polyelectrolyte materialsbased on smectite polyoxyethylene intercalation compoundsrdquoActa Polymerica vol 45 no 2 pp 59ndash67 1994
[8] D Ratna S Divekar A B Samui B C Chakraborty and AK Banthia ldquoPoly(ethylene oxide)clay nanocomposite thermo-mechanical properties andmorphologyrdquo Polymer vol 47 no 11pp 4068ndash4074 2006
[9] D Ratna S Divekar S Patchaiappan A B Samui and BC Chakraborty ldquoPoly(ethylene oxide)clay nanocomposites forsolid polymer electrolyte applicationsrdquo Polymer Internationalvol 56 no 7 pp 900ndash904 2007
[10] S K Lim JW Kim I Chin Y K Kwon andH J Choi ldquoPrepa-ration and interaction characteristics of organically modifiedmontmorillonite nanocomposite with miscible polymer blendof poly(ethylene oxide) and poly(methyl methacrylate)rdquo Chem-istry of Materials vol 14 no 5 pp 1989ndash1994 2002
[11] Y H Hyun S T Lim H J Choi and M S Jhon ldquoRheologyof poly(ethylene oxide)organoclay nanocompositesrdquo Macro-molecules vol 34 no 23 pp 8084ndash8093 2001
10 International Journal of Polymer Science
[12] H-W Chen C-Y Chiu and F-C Chang ldquoConductivity en-hancement mechanism of the poly(ethylene oxide)modified-clayLiClO
4systemsrdquo Journal of Polymer Science Part B Poly-
mer Physics vol 40 no 13 pp 1342ndash1353 2002[13] S Sultana M S Khan and M Humayun ldquoPreparation mor-
phology and thermal and optical properties of thin films offerric chloridepolyethylene oxide compositesrdquo Turkish Journalof Chemistry vol 36 no 5 pp 709ndash716 2012
[14] R Baskaran S Selvasekarapandian N Kuwata J Kawamuraand T Hattori ldquoConductivity and thermal studies of blendpolymer electrolytes based on PVAc-PMMArdquo Solid State Ionicsvol 177 no 26-32 pp 2679ndash2682 2006
[15] S K Lim S T Lim H B Kim I Chin and H J Choi ldquoPrepa-ration and physical characterization of polyepichlorohydrinelastomerclay nanocompositesrdquo Journal of MacromolecularScience Part B Physics vol 42 no 6 pp 1197ndash1208 2003
[16] B Chen and J R G Evans ldquoPreferential intercalation inpolymer-clay nanocompositesrdquo Journal of Physical Chemistry Bvol 108 no 39 pp 14986ndash14990 2004
[17] B Kumar and L G Scanlon ldquoPolymer-ceramic compositeelectrolytes conductivity and thermal history effectsrdquo SolidState Ionics vol 124 no 3 pp 239ndash254 1999
[18] J-H Chang S J Kim Y L Joo and S Im ldquoPoly(ethyleneterephthalate) nanocomposites by in situ interlayer polymeriza-tion the thermo-mechanical properties and morphology of thehybrid fibersrdquo Polymer vol 45 no 3 pp 919ndash926 2004
[19] X Qian N Gu Z Cheng X Yang E Wang and S DongldquoImpedance study of (PEO)
10LiClO
4-Al2O3composite polymer
electrolyte with blocking electrodesrdquo Electrochimica Acta vol46 no 12 pp 1829ndash1836 2001
[20] G J Brug A L G Van den Eeden M Sluyters-Rehbach and JH Sluyters ldquoThe analysis of electrode impedances complicatedby the presence of a constant phase elementrdquo Journal ofElectroanalytical Chemistry and Interfacial Electrochemistry vol176 no 1-2 pp 275ndash295 1984
[21] F Bellucci M Valentino T Monetta et al ldquoImpedance spec-troscopy of reactive polymers 1rdquo Journal of Polymer SciencePart B Polymer Physics vol 32 no 15 pp 2519ndash2527 1994
[22] J T S Irvine D C Sinclair and A R West ldquoElectroceramicscharacterization by impedance spectroscopyrdquo Advanced Mate-rials vol 2 no 3 pp 132ndash138 1990
[23] K V Kumar and G S Sundari ldquoConductivity studies of(PEO +KHCO
3) solid electrolyte system and its application
as an electrochemical cellrdquo Journal of Engineering Science andTechnology vol 5 no 2 pp 130ndash139 2010
[24] P C Srivastava in Solid State Ionics Materials and ApplicationsB V R Chowdar Ed pp 561ndash565 World Scientific Singapore1992
[25] S Ibrahim and M R Johan ldquoConductivity thermal andneural networkmodel nanocomposite solid polymer electrolytesystem (PEO-LiPF6-EC-CNT)rdquo International Journal of Elec-trochemical Science vol 6 no 11 pp 5565ndash5587 2011
[26] P P Chu M J Reddy and J Tsai ldquoStructural and transportcharacteristics of polyethylene oxidephenolic resin blend solidpolymer electrolytesrdquo Journal of Polymer Science Part B Poly-mer Physics vol 42 no 21 pp 3866ndash3875 2004
[27] H-W Chen C-Y Chiu and F-C Chang ldquoConductivityenhancement mechanism of the poly(ethylene oxide)modi-fied-clayLiClO
4systemsrdquo Journal of Polymer Science Part B
Polymer Physics vol 40 no 13 pp 1342ndash1353 2002
[28] K Jeddi N T Qazvini S H Jafari and H A KhonakdarldquoEnhanced ionic conductivity in PEOPMMA glassy misci-ble blends role of nano-confinement of minority componentchainsrdquo Journal of Polymer Science Part B Polymer Physics vol48 no 19 pp 2065ndash2071 2010
[29] S Ramesh and N B Khoo ldquoConductivity mechanical andthermal studies on poly(methyl methacrylate)-based polymerelectrolytes complexed with lithium tetraborate and propylenecarbonaterdquo Journal of Materials Engineering and Performancevol 21 no 1 pp 89ndash94 2012
[30] F Ali Synthesis and characterization of polyimidesilicabased nano-composites material [MPhil Thesis] University ofPeshawar Peshawar Pakistan 2006
[31] S Bai J Chen Z Huang and Z Yu ldquoThe role of the interfacialstrength in glass bead filled HDPErdquo Journal of Materials ScienceLetters vol 19 no 17 pp 1587ndash1589 2000
[32] G Nasar Synthesis and characterization of poly (vinyl alcohol)composites [MPhil thesis] University of Peshawar PeshawarPakistan 2008
[33] A Bandyopadhyay M de Sarkar and A K BhowmickldquoPoly(vinyl alcohol)silica hybrid nanocomposites by sol-geltechnique synthesis and propertiesrdquo Journal of Materials Sci-ence vol 40 no 19 pp 5233ndash5241 2005
[34] H B Kim J S Choi C H Lee S T Lim M S Jhon andH J Choi ldquoPolymer blendorganoclay nanocomposite withpoly(ethylene oxide) and poly(methylmethacrylate)rdquo EuropeanPolymer Journal vol 41 no 4 pp 679ndash685 2005
[35] R L Ledoux and J L White ldquoInfra red studies of hydrogenbonding interaction between kaolinite surfaces and intercalatedpotassium acetate hydrazine formamide and ureardquo Journal ofColloid and Interface Science vol 21 pp 27ndash52 1996
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
4 International Journal of Polymer Science
0
500
1000
1500
2000
2500
0 10 20 30 40 50 60 70
Inte
nsity
(CPS
)
Pure MMTd-valueCPS
100398816398807589391272116544912711571975426686105820803354381592265525721557434852129973884240
199184124550181747303501516879529354301503173106165
2120579
2120579 (∘)
Figure 3 XRD scan of pure MMT
CPC modified MMT
9983272051885782366138311304992571303177544912712001975338419160126602572155803485199387523454516597730555301498793146185
0 10 20 30 40 50 60 700
500
1000
1500
2000
2500
Inte
nsity
(CPS
)
d-valueCPS2120579
2120579 (∘)
Figure 4 XRD scan of CPMMT
increase in gallery spacing which is associated with loweringin surface energy Polymer intercalates within the galleriesas a result of the negative surface charge and the cationichead groups of CPC preferentially reside on the layer surfaceThe salt that is LiClO
4has also interactions with both the
polymer and the negatively charged clay layersComposites of PEOLiClO
4CPMMT were synthesized
with 198 33 462 and 594wt of modified montmoril-lonite loading keeping the mole fraction of salt constantat 35 wt The diffraction patterns of PEOSaltCPMMT(198 (A) 33 (B) 462 (C) and 594 (D) wt) compositesystems are shown in Figure 6 It can be revealed from theseXRD patterns that the PEO has the minimum crystallinitywhen the CPMMT loading is 33 wt This 33 wt ofCPMMT loading was selected as an optimum condition forthe synthesis of the composites The substantial increase inthe intensities of the XRD peaks on increasing CPMMTloadings suggests that the dispersion is better at lower clayloading than at higher loadings This is because the lithiumcation coordinates with the flexible CH
2-O- chain of PEO
forming complexes and thereby disturbing the crystallinityWhen the clay is loaded into the PEOLi ClO
4electrolyte
the crystallinity initially decreases up to 33 wt of clayloading and increases thereafter In case of undoped PEOthe crystallinity gradually decreases with an increase in clayloading because of the steric hindrance caused by the hugesurface area of randomly oriented clay throughout thematrixThe different crystallization behaviors of PEOLiClO
4clay
composite electrolyte and PEOClay composite is explainedby considering the fact that negatively charged clay layers
also coordinate with the lithium cation due to a strongelectrostatic interaction The interaction depends on theexpansion of silicate layers and clay content Because of thisinteraction PEO to Li+ interactions decrease and crystallinityincreases Thus two competing effects are present in thePEOLiClO
4Clay composite electrolyte one reduces the
crystallinity and the other favors the crystallinity At low clayloading the first factor predominates leading to a decrease inthe crystallinity and beyond the optimumclay concentrationsthe second factor predominates over the first resulting inhigher crystallinity [16 17] The presence of the CPMMThowever had no effect on the location of the peaks whichindicates that perfect exfoliation of the clay layer structureof the organoclay in PEO does not occur [18] The XRDpatterns of the fabricated composites show that most of thepeaks corresponding to pure LiClO
4have disappeared in the
composite system which reveals the dissolution of the saltin the polymer matrix Similarly the appearance of some ofthe peaks of the LiClO
4in the composite system confirms the
complexation of the salt with the polymer matrix
32 X-Ray Diffraction Analysis of PEOLiClO4(Variable)
CPMMT(33 wt) Composite System X-ray diffraction anal-ysis of PEOLiClO
4CPMMT composite with 33 wt of
CPMMT clay at varying concentrations of salt is shown inFigure 7 which depicts that PEOLiClO
4clay composites
first show decrease in crystallinity of PEOwith the increasingamount of salt but when the concentration of salt is increasedfrom PCS2 that is 35 wt the crystalline character of PEOstarts increasing this is attributed to the local aggregationof inorganic particles at higher salt concentration The sameresult ismanifested by ourmechanical and Scanning ElectronMicroscopy (SEM) studies
33 X-Ray Diffraction Analysis of PEOPMMALiClO4(Vari-
able)CPMMT(33 wt) BlendComposite System In order toinvestigate the effect of poly(methyl methacrylate) (PMMA)addition on the crystallinity of PEO in the blend compositeof PEOPMMALiClO
4CPMMT having variable concentra-
tions of salt and constant clay content (of 33 wt) X-rayanalysis was carried out From the diffractogram patterngiven in Figure 8 it is clear that though PMMA is amorphousin nature its addition to the composite system has no sig-nificant effect on the system The crystalline fraction of PEOincreased a little bit by its additionThis is because the amountof PEO in PEOPMMA blend is far more than overlap weightfraction (119882lowast) which causes PEO to crystallize and alsobecause PMMA interaction with CPMMT is more than thatof PEO which affects the properties of PEO when present inblendThe d-spacing between the layers of the system is foundto be decreasing (Table 1) which also accounts for increaseof crystalline behavior This result is consistent with our ACimpedance study and is also supported by the literature [18]
34 Ionic Conductivity of PEO Composite and Blend Compos-ite System In a Nyquist impedance plot the real part (119885) ofthe impedance was plotted against the imaginary part (119885)for data collected at frequencies ranging from 1 to 107Hz
International Journal of Polymer Science 5
OO
OO
OO
O
O
O
OO
O
O
OO
OO
OO
O
O
O
OO
O
O
OO
O
O
OO
OO
O
O
OO
O
O
OO
OO
O
O
OO
OO
O
O
OO
O
O
OO
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+N
+
N+
N+
N+
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+
N+
N+
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+N
+
N+
N+
N+
CH3 CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3 CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3 CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3CH3
CH3
CH3CH3CH3CH3
CPMMT Polymer
O O O
O
O O OO
O
O
O O
O
O
OO
OOO
O
OOOO
O
O
OO
O
O
OO
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
N+
N+
N+
CH3 CH3
CH3CH3
LiCIO4
OOO
O
OOOO
O
O
OO
O
O
OO
O O O
O
O O OO
O
O
O O
O
O
OO
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3 N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3 N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N
+
CH3N
+
CH3N
+
CH3N
+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N
+
CH3N
+
CH3N
+
CH3N
+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
Li+
CIO4minus
NN+
NN+
CH3
NN+
3
NNNNNN
CHC 3
NNN
CHC 3
CHC 3 NNN+
CH3
NNN+
CH3
NNN+
CH3
NNN+
CH3
NN+
CH3
NN+
CH3
NN+
CH3
NN+
CH3
NNN++
CH3
NNN++
CH3
NNN++
CH3
NNN++
CH3
NNN+
CHC 3
NNN+
CHC 3
NNN+
CHC 3
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
Figure 5 Mechanism of PEO-SaltCPMMT interaction
To investigate complete picture of the system an equivalentcircuit was used [19]The bulk resistance of the solid polymerelectrolyte (SPE) was consequent from the equivalent circuitFigures 9(a) 9(b) 9(c) and 9(d) show theNyquist impedanceplots for PEOLiClO
4 denoted as PS (a) PEOLiClO
4
after fitting to equivalent circuit (b) PEOCPMMTLiClO4
denoted as PCS (c) PEOPMMACPMMTLiClO4denoted
as PPCS (d) and impedance plot after fitting to the equiv-alent circuit respectively These diagrams deviate from anideal impedance spectrum that usually exhibits a standardsemicircle at the high frequency section and a vertical lineat a lower frequency section The deformed semicircle andthe inclined line for the polymeric filmelectrode systemmay be attributed to the irregular thickness and morphologyof the polymeric film and the roughness of the electrodesurface [20 21] To investigate the phenomenon a ldquoconstantphase elementrdquo (CPE) was employed in the equivalent circuitThe high frequency semicircle depicts the combination ofR1 and CPE-1 while the spike showing the trend for second
semicircle due to double layer capacitance (at the interface ofsolid polymer electrolyte and electrode) is reflected by CPE-2 [19] The equivalent circuit used for fitting data and tablefor parameters for the circuit elements evaluated by fittingthe impedance data for composite and blend system at roomtemperature (15∘C) is given in Figure 9 as inset
From equivalent circuits the bulk resistance values wereobtained The bulk resistance allows us to obtain the ionicconductivity using
120590 =
119868
119877119860
(1)
where 120590 = conductivity (Scm) 119877 = resistance (Ω) 119868 =thickness (cm) and 119860 = area of the electrode (cm2)
The capacitance values were calculated according to120596max119877119862=1 (2)
where 120596max corresponds to the frequency at the maximum ofsemicircle The capacitance values obtained for the bulk arein complete harmony with the earlier reported values [22]
6 International Journal of Polymer Science
(A)
(B)
(C)
(D)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 6 Combined XRD pattern of PEOSalt composite systemwith 198 (A) 33 (B) 462 (C) and 594 (D) wt of CPMMT
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 7 Combined XRD scans of PEOCPMMTSalt (PCS1)(21 wt A) PEOCPMMTSalt (PCS2) (35 wt B) and PEOCPMMTSalt (PCS3) (5 wt C)
The value of ionic conductivity obtained at room tem-perature (15∘C) for pure poly(ethylene oxide) (PEO) is lessthan 678 times 10minus10 S cmminus1 reported in the literature earlier byKumar and coworker [17] for the samemolecular weight PEOat 30∘C This difference in conductivity values is because ofthe temperature and changing nature of solvent used in ourstudy [23] From the table given as inset in Figure 10 it isclear that the conductivity of PEO at laboratory temperaturethat is 15∘C increases sharplywith the salt incorporationThe
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 8 Combined XRD scans of PEOPMMACPMMTSalt(PPCS1) (21 wt A) PEOPMMACPMMTSalt (PPCS2) (35 wtB) and PEOPMMACPMMTSalt (PPCS3) (5 wt C)
same trend in conductivity of PEO based electrolytes withthe salt concentration has also been observed by Srivastavaand Ibrahim et al [24 25] This increase is due to theincrease in charge carriers caused by the addition of higherconcentration of LiClO
4and the increase in the fraction of
amorphous phaseThe addition of ionic salt decreases degra-dation temperature because of the growth of amorphous frac-tion and destabilizes the polymer network The PEOLiClO
4
electrolyte with high salt concentration was found to be lessstable Alternatively CPMMT was used to overcome thesedrawbacks Inorganic fillers are usually used to improvethe electrochemical and mechanical properties [26] Clay isinorganic filler with intercalation property where clay layersmaintain their registry Intercalating polymer (residing poly-mer chains between silicates) in a layered clay host can pro-duce huge interfacial area to sustain the mechanical propertyof polymer electrolyte system and impart salt solvating powerto dissolve the lithium salt [27] A glance at Figure 10 and insettable reveals that the addition of salt at constant (33 wt)clay content increases the conductivity of PEOSaltCPMMT(PCS) composites retaining dimensional stability till PCS2(35 wt) beyond PCS2 further addition of salt decreases theconductivity badlyThis initial increase is due to the decreasein the crystallinity and increase in amorphous fraction ofPEO for ion conduction till equilibrium is achieved at PCS2This is consistent with our XRD results The conductivitydecreases drastically when amount of salt increases fromPCS2 to PCS3 (5wt) but is still higher than that of pristinepolymer The possible explanation for this behavior may beion association and the formation of charge multipliers [25]In order to study the effect of poly(methyl methacrylate)(PMMA) incorporation on the ionic conductivity of PEObased solid polymer electrolytes PMMA was blended with
International Journal of Polymer Science 7
1e6 2e6 3e6 4e600
minus1e6
minus2e6
minus3e6
minus4e6
Z998400
PEOLiClO4
N998400998400
(a)
Samples PS PCS PPCS661410 169520
CPE1-TCPE1-P 0922 09848 0535CPE2-TCPE2-P 0864 0715 08156
50000 100000 15000000
minus50000
minus100000
minus150000
Z998400
R1Ω 127 times 106
965 times 10minus11
544 times 10minus11
622 times 10minus11
946 times 10minus9
882 times 10minus9
877 times 10minus10
CPE1CPE2 CPE2R1
N998400998400
(b)
1e6 2e6 3e6 5e64e60
Z998400
0
minus1e6
minus2e6
minus3e6
minus5e6
minus4e6
PEOCPMMTLiClO4
N998400998400
(c)
1e7 2e7 3e70
Z998400
0
minus1e7
minus2e7
minus3e7PEOPMMACPMMTLiClO4
N998400998400
(d)
Figure 9 Typical Nyquist impedance plots for PEOSalt (PS) (a) PEOSalt (PS) after fitting to equivalent circuit (b) Inset showing thatdiagram of circuit and extracted parameters for the circuit elements of PS PCS and PPCS are summarized in the table PEOSaltCPMMT(PCS) (c) PEOPMMASaltCPMMT (PPCS) (d)
PEO for solid polymer electrolyte (SPE) composites Fromthe values of ionic conductivity given in Figure 10 and insettable it is clear that the addition of PMMA to PEOSaltelectrolyte system decreases the conductivity of PCS systembut still shows higher value than pure PEO films The rigidstructure of PMMA due to the entrapped silicate layersalters the segmental dynamics of PEO so there is decreasein conductivity Jeddi and coworkers [28] have reported anoverlapweight fraction for PEOPMMAblendwhich is about28 wt for PEO Overlap weight fraction is that weight atwhich PEO starts interpenetration and miscibility of blendsis affected In our system the amount of PEO is far more thanoverlap weight fraction So it causes decrease in conductivityand an increase in the agglomeration of clay by decreasing itsinteraction with the PEOThe same trend has been observed
in mechanical properties of the PEOPMMASaltCPMMT(PPCS) composites The values of ionic conductivity wereached at laboratory temperature of 15∘C are higher thanthose reported for the PEOPMMAsaltNa-MMT in theliterature at 25∘C [22] This increase may be caused by thebetter dispersion of CPMMT
35 Elongation at Break of PEOLiClO4CPMMT Composite
System Elongation at break is the strain at failure or percentchange at failure and explains the ductility of the materialwith external forceThe effect of salt addition on the ductilityor elongation is shown in Figure 11 The result fromFigure 11 depicts that ductility of the composite materialincreases with increasing salt concentration in the resultingcomposites This increase is attributed to the presence of
8 International Journal of Polymer Science
0 1 2 3 4 5 6
PPSCPSC
Salt concentration (wt)
Film codeP0PCPCS1PCS2PCS3PPCS1PPCS2PPCS3
minus1
minus7
minus8
minus9
minus10
minus11
minus12
726 times 10minus12
1017 times 10minus7
5 times 10minus10
294 times 10minus8
556 times 10minus11
220 times 10minus10
424 times 10minus9
331 times 10minus9
Bulk 120590 (Scm)
Log120590
(S cm
minus1)
Figure 10 Bulk ionic conductivity variation for PSC and PPSCwithweight of salt for composite system at room temperature (15∘C)
0
100
200
300
400
500
600
0
5
10
15
20
25
0 1 2 3 4 5 6Salt concentration (wt)
minus1
Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
clay)
syste
m
and
(PEO
+PM
MA+
clay)
PEO + clay
PEO + PMMA
PEO + PMMA + clay Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
PMM
A)
Figure 11 Variation of elongation at break for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
CPMMT which enhances the mobility of the PEO polymerThe highest elongation at break is obtained for the PCS2composite and beyond PCS2 elongation at break decreasesThe higher uniformity in the dispersion of salt and claywithin PEO is correlated with better adhesion between thecomponents of the composite due to the homogeneousdispersion of CPCMMT at PCS2 composition The decreasein the ductility beyond PCS2 is due to the restriction inchain mobility of the matrix and the filler particles acting asdefect points [29] This also shows that beyond certain limitof salt concentration the behavior changes Further at higher
20
40
60
80
100
120
140
160
0
200
400
600
800
1000
0 1 2 3 4 5 6Salt concentration (wt)
PEO + clay
PEO + PMMA
PEO + PMMA + clay
minus1
s mod
ulus
(Nm
m2) f
or (P
EO+
clay)
syste
mYo
ungrsquo
s mod
ulus
(Nm
m2)
and
(PEO
+PM
MA+
clay)
for (
PEO+
PMM
A)
Youn
grsquo
Figure 12 Variations of Youngrsquos modulus for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
concentrations the polymers exist in agglomeration and theclay is not well dispersed The overall result is the increasein the ductility of the composite material with increasingsalt concentration The net increase in elongation at breakfor PCS system suggests filler induced dimensional stabilityto the composite electrolyte films making them capable ofsustaining and withstanding any external pressureshock to abetter level
36 Youngrsquos Modulus of PEOLiClO4CPMMT Composites
Youngrsquos modulus is a variable that describes the relationshipof stress to strain within the elastic region This is measuredfrom the slope of the curve within the elastic area of thespecimen The modulus of elasticity describes a materialrsquosstiffness the greater the modulus the stiffer the material Itquantifies the elasticity of the polymerIt is truly associatedwith primary and secondary chemical bonds Unlike the neatpolymer where the mechanical properties are determinedalmost entirely by matrix the mechanical properties of thecomposite depend on the interaction between the polymerand the added fillers From Figure 12 it is clear that Youngrsquosmodulus of the composites electrolyte decreases with theincreasing concentration of inorganic contents at constantclay levelThe influence of LiClO
4on the mechanical proper-
ties of PEOCPMMT film resembles the plasticization effectThe interaction between PEO and CPMMT is weakened bythe increasing content of salt The same behavior of Youngrsquosmodulus with filler has been reported earlier in the literature[29] As mechanical properties change by changing thecomposition of components as well as with the applied forcethey are difficult to analyze Also this decrease may probablybe explained in terms of debonding around polymer andclay interphases and void formation It can be concluded thatvalue of modulus depends highly on the distribution of fillerparticles in the polymer matrix which in turn depends on
International Journal of Polymer Science 9
the particleparticle interaction (agglomeration) andpolymerparticle interaction (adhesion and wetting) and morphologyof the filler particles [30]
37 Elongations at Break of PEOPMMALiClO4CPMMTBlend Composites System In order to have a more clear ideaof the change inmechanical properties of the blend compositesystem first the addition of salt to the blend system wasstudied for its effect on the mechanical properties and thenCPMMT was added to the same system and the sampleswere analyzed by UTM From the results given in Figure 11it is clear that elongation at break decreases initially withthe increasing concentration of salt to the blend system andthen starts increasing with higher salt concentration Thisdecrease in failure strain is due to the rigid filler additionwhich restricts the mobility of the PEO polymermolecules toflow freely past one another thus causing premature failureThe original elasticity of PEO is distorted due to the additionof PMMA and LiClO
4which is in close agreement with the
conclusion that the addition of rigid particles like PMMAinto the polymer matrix increases its stiffness and toughness[31 32] Compositeswith these properties can be used for heatresistant materials or product packaging materials
38 Youngrsquos Modulus of PEOPMMALiClO4CPMM Blend
Composites System Youngrsquos modulus of the PEOPMMA asa function of salt is shown in Figure 12 From this Figure itis clear that Youngrsquos modulus of the blend composite showsan overall decrease with the addition of salt This decreaseshows the weaker PEO interchain interaction and increasein the particle size of the inorganic phase because of localaggregations of particles in the presence of PMMA thesephenomenamay act as flaws in it [33 34]The same trend hasbeen confirmed by the SEM result as well This means thatthe addition of salt to the PEOPMMA composite suppressesthematerialrsquos stiffness and hence elasticity of the polymer Butwhen clay was added to the same PEOPMMASalt systeman enormous increase in the value of Young modulus wasobserved as shown in Figure 12 This is due to the interca-lation of polymer chains within the clay galleries that avoidsegmental motion of the polymer chains [35] Although thereis an overall decrease in the value of Young modulus of thePEOPMMALiClO
4CPMMT system with increasing salt
concentration still it is much higher than that of the virgin(neat) poly(ethylene oxide) (PEO) and PEOSaltCPMMTThis is in close agreement with the conclusion that theaddition of rigid particles like PMMA into the polymermatrix increases its stiffness [31]
4 Conclusions
This work used cetylpyridinium chloride to modify MMTmixed with higher molecular weight PEOLiClO
4and
PEOPMMALiClO4to produce composite materials The
experimental results showed that at constant salt contentthe addition of CPMMT first reduces crystallinity of PEOtill 33 wt of clay and then starts increasing at higher claycontent Thus 33 wt of clay was selected as the optimum
clay loadings for composites fabrication The XRD resultsshowed that the crystallinity of composites at optimum clayloading increases with increasing salt content and ionicconductivity obtained from impedance technique showeddeclining trend with higher salt content The addition of50wt of higher molecular weight PMMA to the com-posite of PEOSaltCPMMT affected the properties due tothe immiscibility or aggregation of filler within the poly-mer matrix however the blend composites showed bettermechanical performanceThe composite of PEOwith 35 wtof salt and 33 wt of CPMMT exhibited better performance
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] S Sultana Fabrication and studies on thin film composites ofPoly (Ethylene Oxide) [PhD thesis] University of PeshawarPeshawar Pakistan 2013
[2] T Lan P D Kaviratna and T J Pinnavaia ldquoEpoxy self-polymerization in smectite claysrdquo Journal of Physics and Chem-istry of Solids vol 57 no 6-8 pp 1005ndash1010 1996
[3] X Q Yang H S Lee L Hanson J McBreen and Y OkamotoldquoDevelopment of a new plasticizer for poly(ethylene oxide)-based polymer electrolyte and the investigation of their ion-pairdissociation effectrdquo Journal of Power Sources vol 54 no 2 pp198ndash204 1995
[4] R Mishra and K J Rao ldquoElectrical conductivity studies ofpoly(ethyleneoxide)-poly(vinylalcohol) blendsrdquo Solid State Ion-ics vol 106 no 1-2 pp 113ndash127 1998
[5] M S Khan A Shakoor and J Nisar ldquoConductance study ofpoly(ethylene oxide)- and poly(propylene oxide)-based poly-electrolytesrdquo Ionics vol 16 no 6 pp 539ndash542 2010
[6] Z Shen G P Simon and Y-B Cheng ldquoComparison ofsolution intercalation and melt intercalation of polymer-claynanocompositesrdquo Polymer vol 43 no 15 pp 4251ndash4260 2002
[7] P Aranda and E Ruiz-Hitzky ldquoNew polyelectrolyte materialsbased on smectite polyoxyethylene intercalation compoundsrdquoActa Polymerica vol 45 no 2 pp 59ndash67 1994
[8] D Ratna S Divekar A B Samui B C Chakraborty and AK Banthia ldquoPoly(ethylene oxide)clay nanocomposite thermo-mechanical properties andmorphologyrdquo Polymer vol 47 no 11pp 4068ndash4074 2006
[9] D Ratna S Divekar S Patchaiappan A B Samui and BC Chakraborty ldquoPoly(ethylene oxide)clay nanocomposites forsolid polymer electrolyte applicationsrdquo Polymer Internationalvol 56 no 7 pp 900ndash904 2007
[10] S K Lim JW Kim I Chin Y K Kwon andH J Choi ldquoPrepa-ration and interaction characteristics of organically modifiedmontmorillonite nanocomposite with miscible polymer blendof poly(ethylene oxide) and poly(methyl methacrylate)rdquo Chem-istry of Materials vol 14 no 5 pp 1989ndash1994 2002
[11] Y H Hyun S T Lim H J Choi and M S Jhon ldquoRheologyof poly(ethylene oxide)organoclay nanocompositesrdquo Macro-molecules vol 34 no 23 pp 8084ndash8093 2001
10 International Journal of Polymer Science
[12] H-W Chen C-Y Chiu and F-C Chang ldquoConductivity en-hancement mechanism of the poly(ethylene oxide)modified-clayLiClO
4systemsrdquo Journal of Polymer Science Part B Poly-
mer Physics vol 40 no 13 pp 1342ndash1353 2002[13] S Sultana M S Khan and M Humayun ldquoPreparation mor-
phology and thermal and optical properties of thin films offerric chloridepolyethylene oxide compositesrdquo Turkish Journalof Chemistry vol 36 no 5 pp 709ndash716 2012
[14] R Baskaran S Selvasekarapandian N Kuwata J Kawamuraand T Hattori ldquoConductivity and thermal studies of blendpolymer electrolytes based on PVAc-PMMArdquo Solid State Ionicsvol 177 no 26-32 pp 2679ndash2682 2006
[15] S K Lim S T Lim H B Kim I Chin and H J Choi ldquoPrepa-ration and physical characterization of polyepichlorohydrinelastomerclay nanocompositesrdquo Journal of MacromolecularScience Part B Physics vol 42 no 6 pp 1197ndash1208 2003
[16] B Chen and J R G Evans ldquoPreferential intercalation inpolymer-clay nanocompositesrdquo Journal of Physical Chemistry Bvol 108 no 39 pp 14986ndash14990 2004
[17] B Kumar and L G Scanlon ldquoPolymer-ceramic compositeelectrolytes conductivity and thermal history effectsrdquo SolidState Ionics vol 124 no 3 pp 239ndash254 1999
[18] J-H Chang S J Kim Y L Joo and S Im ldquoPoly(ethyleneterephthalate) nanocomposites by in situ interlayer polymeriza-tion the thermo-mechanical properties and morphology of thehybrid fibersrdquo Polymer vol 45 no 3 pp 919ndash926 2004
[19] X Qian N Gu Z Cheng X Yang E Wang and S DongldquoImpedance study of (PEO)
10LiClO
4-Al2O3composite polymer
electrolyte with blocking electrodesrdquo Electrochimica Acta vol46 no 12 pp 1829ndash1836 2001
[20] G J Brug A L G Van den Eeden M Sluyters-Rehbach and JH Sluyters ldquoThe analysis of electrode impedances complicatedby the presence of a constant phase elementrdquo Journal ofElectroanalytical Chemistry and Interfacial Electrochemistry vol176 no 1-2 pp 275ndash295 1984
[21] F Bellucci M Valentino T Monetta et al ldquoImpedance spec-troscopy of reactive polymers 1rdquo Journal of Polymer SciencePart B Polymer Physics vol 32 no 15 pp 2519ndash2527 1994
[22] J T S Irvine D C Sinclair and A R West ldquoElectroceramicscharacterization by impedance spectroscopyrdquo Advanced Mate-rials vol 2 no 3 pp 132ndash138 1990
[23] K V Kumar and G S Sundari ldquoConductivity studies of(PEO +KHCO
3) solid electrolyte system and its application
as an electrochemical cellrdquo Journal of Engineering Science andTechnology vol 5 no 2 pp 130ndash139 2010
[24] P C Srivastava in Solid State Ionics Materials and ApplicationsB V R Chowdar Ed pp 561ndash565 World Scientific Singapore1992
[25] S Ibrahim and M R Johan ldquoConductivity thermal andneural networkmodel nanocomposite solid polymer electrolytesystem (PEO-LiPF6-EC-CNT)rdquo International Journal of Elec-trochemical Science vol 6 no 11 pp 5565ndash5587 2011
[26] P P Chu M J Reddy and J Tsai ldquoStructural and transportcharacteristics of polyethylene oxidephenolic resin blend solidpolymer electrolytesrdquo Journal of Polymer Science Part B Poly-mer Physics vol 42 no 21 pp 3866ndash3875 2004
[27] H-W Chen C-Y Chiu and F-C Chang ldquoConductivityenhancement mechanism of the poly(ethylene oxide)modi-fied-clayLiClO
4systemsrdquo Journal of Polymer Science Part B
Polymer Physics vol 40 no 13 pp 1342ndash1353 2002
[28] K Jeddi N T Qazvini S H Jafari and H A KhonakdarldquoEnhanced ionic conductivity in PEOPMMA glassy misci-ble blends role of nano-confinement of minority componentchainsrdquo Journal of Polymer Science Part B Polymer Physics vol48 no 19 pp 2065ndash2071 2010
[29] S Ramesh and N B Khoo ldquoConductivity mechanical andthermal studies on poly(methyl methacrylate)-based polymerelectrolytes complexed with lithium tetraborate and propylenecarbonaterdquo Journal of Materials Engineering and Performancevol 21 no 1 pp 89ndash94 2012
[30] F Ali Synthesis and characterization of polyimidesilicabased nano-composites material [MPhil Thesis] University ofPeshawar Peshawar Pakistan 2006
[31] S Bai J Chen Z Huang and Z Yu ldquoThe role of the interfacialstrength in glass bead filled HDPErdquo Journal of Materials ScienceLetters vol 19 no 17 pp 1587ndash1589 2000
[32] G Nasar Synthesis and characterization of poly (vinyl alcohol)composites [MPhil thesis] University of Peshawar PeshawarPakistan 2008
[33] A Bandyopadhyay M de Sarkar and A K BhowmickldquoPoly(vinyl alcohol)silica hybrid nanocomposites by sol-geltechnique synthesis and propertiesrdquo Journal of Materials Sci-ence vol 40 no 19 pp 5233ndash5241 2005
[34] H B Kim J S Choi C H Lee S T Lim M S Jhon andH J Choi ldquoPolymer blendorganoclay nanocomposite withpoly(ethylene oxide) and poly(methylmethacrylate)rdquo EuropeanPolymer Journal vol 41 no 4 pp 679ndash685 2005
[35] R L Ledoux and J L White ldquoInfra red studies of hydrogenbonding interaction between kaolinite surfaces and intercalatedpotassium acetate hydrazine formamide and ureardquo Journal ofColloid and Interface Science vol 21 pp 27ndash52 1996
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
International Journal of Polymer Science 5
OO
OO
OO
O
O
O
OO
O
O
OO
OO
OO
O
O
O
OO
O
O
OO
O
O
OO
OO
O
O
OO
O
O
OO
OO
O
O
OO
OO
O
O
OO
O
O
OO
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+N
+
N+
N+
N+
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+
N+
N+
N+
N+
N+ N
+
N+
N+
N+
N+
N+
N+
N+
N+
N+N
+
N+N
+
N+
N+
N+
CH3 CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3 CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3 CH3
CH3
CH3CH3
CH3
CH3
CH3
CH3
CH3CH3
CH3
CH3CH3
CH3
CH3CH3CH3CH3
CPMMT Polymer
O O O
O
O O OO
O
O
O O
O
O
OO
OOO
O
OOOO
O
O
OO
O
O
OO
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
N+
N+
N+
CH3 CH3
CH3CH3
LiCIO4
OOO
O
OOOO
O
O
OO
O
O
OO
O O O
O
O O OO
O
O
O O
O
O
OO
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
N+
N+
N+
CH3
CH3
CH3
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3 N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3 N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N
+
CH3N
+
CH3N
+
CH3N
+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3N
+
CH3N
+
CH3N
+
CH3N
+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
N+
CH3
Li+
CIO4minus
NN+
NN+
CH3
NN+
3
NNNNNN
CHC 3
NNN
CHC 3
CHC 3 NNN+
CH3
NNN+
CH3
NNN+
CH3
NNN+
CH3
NN+
CH3
NN+
CH3
NN+
CH3
NN+
CH3
NNN++
CH3
NNN++
CH3
NNN++
CH3
NNN++
CH3
NNN+
CHC 3
NNN+
CHC 3
NNN+
CHC 3
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
OO
O
O
OO
O
O
O
O
OO
O
O
O
O
Figure 5 Mechanism of PEO-SaltCPMMT interaction
To investigate complete picture of the system an equivalentcircuit was used [19]The bulk resistance of the solid polymerelectrolyte (SPE) was consequent from the equivalent circuitFigures 9(a) 9(b) 9(c) and 9(d) show theNyquist impedanceplots for PEOLiClO
4 denoted as PS (a) PEOLiClO
4
after fitting to equivalent circuit (b) PEOCPMMTLiClO4
denoted as PCS (c) PEOPMMACPMMTLiClO4denoted
as PPCS (d) and impedance plot after fitting to the equiv-alent circuit respectively These diagrams deviate from anideal impedance spectrum that usually exhibits a standardsemicircle at the high frequency section and a vertical lineat a lower frequency section The deformed semicircle andthe inclined line for the polymeric filmelectrode systemmay be attributed to the irregular thickness and morphologyof the polymeric film and the roughness of the electrodesurface [20 21] To investigate the phenomenon a ldquoconstantphase elementrdquo (CPE) was employed in the equivalent circuitThe high frequency semicircle depicts the combination ofR1 and CPE-1 while the spike showing the trend for second
semicircle due to double layer capacitance (at the interface ofsolid polymer electrolyte and electrode) is reflected by CPE-2 [19] The equivalent circuit used for fitting data and tablefor parameters for the circuit elements evaluated by fittingthe impedance data for composite and blend system at roomtemperature (15∘C) is given in Figure 9 as inset
From equivalent circuits the bulk resistance values wereobtained The bulk resistance allows us to obtain the ionicconductivity using
120590 =
119868
119877119860
(1)
where 120590 = conductivity (Scm) 119877 = resistance (Ω) 119868 =thickness (cm) and 119860 = area of the electrode (cm2)
The capacitance values were calculated according to120596max119877119862=1 (2)
where 120596max corresponds to the frequency at the maximum ofsemicircle The capacitance values obtained for the bulk arein complete harmony with the earlier reported values [22]
6 International Journal of Polymer Science
(A)
(B)
(C)
(D)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 6 Combined XRD pattern of PEOSalt composite systemwith 198 (A) 33 (B) 462 (C) and 594 (D) wt of CPMMT
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 7 Combined XRD scans of PEOCPMMTSalt (PCS1)(21 wt A) PEOCPMMTSalt (PCS2) (35 wt B) and PEOCPMMTSalt (PCS3) (5 wt C)
The value of ionic conductivity obtained at room tem-perature (15∘C) for pure poly(ethylene oxide) (PEO) is lessthan 678 times 10minus10 S cmminus1 reported in the literature earlier byKumar and coworker [17] for the samemolecular weight PEOat 30∘C This difference in conductivity values is because ofthe temperature and changing nature of solvent used in ourstudy [23] From the table given as inset in Figure 10 it isclear that the conductivity of PEO at laboratory temperaturethat is 15∘C increases sharplywith the salt incorporationThe
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 8 Combined XRD scans of PEOPMMACPMMTSalt(PPCS1) (21 wt A) PEOPMMACPMMTSalt (PPCS2) (35 wtB) and PEOPMMACPMMTSalt (PPCS3) (5 wt C)
same trend in conductivity of PEO based electrolytes withthe salt concentration has also been observed by Srivastavaand Ibrahim et al [24 25] This increase is due to theincrease in charge carriers caused by the addition of higherconcentration of LiClO
4and the increase in the fraction of
amorphous phaseThe addition of ionic salt decreases degra-dation temperature because of the growth of amorphous frac-tion and destabilizes the polymer network The PEOLiClO
4
electrolyte with high salt concentration was found to be lessstable Alternatively CPMMT was used to overcome thesedrawbacks Inorganic fillers are usually used to improvethe electrochemical and mechanical properties [26] Clay isinorganic filler with intercalation property where clay layersmaintain their registry Intercalating polymer (residing poly-mer chains between silicates) in a layered clay host can pro-duce huge interfacial area to sustain the mechanical propertyof polymer electrolyte system and impart salt solvating powerto dissolve the lithium salt [27] A glance at Figure 10 and insettable reveals that the addition of salt at constant (33 wt)clay content increases the conductivity of PEOSaltCPMMT(PCS) composites retaining dimensional stability till PCS2(35 wt) beyond PCS2 further addition of salt decreases theconductivity badlyThis initial increase is due to the decreasein the crystallinity and increase in amorphous fraction ofPEO for ion conduction till equilibrium is achieved at PCS2This is consistent with our XRD results The conductivitydecreases drastically when amount of salt increases fromPCS2 to PCS3 (5wt) but is still higher than that of pristinepolymer The possible explanation for this behavior may beion association and the formation of charge multipliers [25]In order to study the effect of poly(methyl methacrylate)(PMMA) incorporation on the ionic conductivity of PEObased solid polymer electrolytes PMMA was blended with
International Journal of Polymer Science 7
1e6 2e6 3e6 4e600
minus1e6
minus2e6
minus3e6
minus4e6
Z998400
PEOLiClO4
N998400998400
(a)
Samples PS PCS PPCS661410 169520
CPE1-TCPE1-P 0922 09848 0535CPE2-TCPE2-P 0864 0715 08156
50000 100000 15000000
minus50000
minus100000
minus150000
Z998400
R1Ω 127 times 106
965 times 10minus11
544 times 10minus11
622 times 10minus11
946 times 10minus9
882 times 10minus9
877 times 10minus10
CPE1CPE2 CPE2R1
N998400998400
(b)
1e6 2e6 3e6 5e64e60
Z998400
0
minus1e6
minus2e6
minus3e6
minus5e6
minus4e6
PEOCPMMTLiClO4
N998400998400
(c)
1e7 2e7 3e70
Z998400
0
minus1e7
minus2e7
minus3e7PEOPMMACPMMTLiClO4
N998400998400
(d)
Figure 9 Typical Nyquist impedance plots for PEOSalt (PS) (a) PEOSalt (PS) after fitting to equivalent circuit (b) Inset showing thatdiagram of circuit and extracted parameters for the circuit elements of PS PCS and PPCS are summarized in the table PEOSaltCPMMT(PCS) (c) PEOPMMASaltCPMMT (PPCS) (d)
PEO for solid polymer electrolyte (SPE) composites Fromthe values of ionic conductivity given in Figure 10 and insettable it is clear that the addition of PMMA to PEOSaltelectrolyte system decreases the conductivity of PCS systembut still shows higher value than pure PEO films The rigidstructure of PMMA due to the entrapped silicate layersalters the segmental dynamics of PEO so there is decreasein conductivity Jeddi and coworkers [28] have reported anoverlapweight fraction for PEOPMMAblendwhich is about28 wt for PEO Overlap weight fraction is that weight atwhich PEO starts interpenetration and miscibility of blendsis affected In our system the amount of PEO is far more thanoverlap weight fraction So it causes decrease in conductivityand an increase in the agglomeration of clay by decreasing itsinteraction with the PEOThe same trend has been observed
in mechanical properties of the PEOPMMASaltCPMMT(PPCS) composites The values of ionic conductivity wereached at laboratory temperature of 15∘C are higher thanthose reported for the PEOPMMAsaltNa-MMT in theliterature at 25∘C [22] This increase may be caused by thebetter dispersion of CPMMT
35 Elongation at Break of PEOLiClO4CPMMT Composite
System Elongation at break is the strain at failure or percentchange at failure and explains the ductility of the materialwith external forceThe effect of salt addition on the ductilityor elongation is shown in Figure 11 The result fromFigure 11 depicts that ductility of the composite materialincreases with increasing salt concentration in the resultingcomposites This increase is attributed to the presence of
8 International Journal of Polymer Science
0 1 2 3 4 5 6
PPSCPSC
Salt concentration (wt)
Film codeP0PCPCS1PCS2PCS3PPCS1PPCS2PPCS3
minus1
minus7
minus8
minus9
minus10
minus11
minus12
726 times 10minus12
1017 times 10minus7
5 times 10minus10
294 times 10minus8
556 times 10minus11
220 times 10minus10
424 times 10minus9
331 times 10minus9
Bulk 120590 (Scm)
Log120590
(S cm
minus1)
Figure 10 Bulk ionic conductivity variation for PSC and PPSCwithweight of salt for composite system at room temperature (15∘C)
0
100
200
300
400
500
600
0
5
10
15
20
25
0 1 2 3 4 5 6Salt concentration (wt)
minus1
Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
clay)
syste
m
and
(PEO
+PM
MA+
clay)
PEO + clay
PEO + PMMA
PEO + PMMA + clay Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
PMM
A)
Figure 11 Variation of elongation at break for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
CPMMT which enhances the mobility of the PEO polymerThe highest elongation at break is obtained for the PCS2composite and beyond PCS2 elongation at break decreasesThe higher uniformity in the dispersion of salt and claywithin PEO is correlated with better adhesion between thecomponents of the composite due to the homogeneousdispersion of CPCMMT at PCS2 composition The decreasein the ductility beyond PCS2 is due to the restriction inchain mobility of the matrix and the filler particles acting asdefect points [29] This also shows that beyond certain limitof salt concentration the behavior changes Further at higher
20
40
60
80
100
120
140
160
0
200
400
600
800
1000
0 1 2 3 4 5 6Salt concentration (wt)
PEO + clay
PEO + PMMA
PEO + PMMA + clay
minus1
s mod
ulus
(Nm
m2) f
or (P
EO+
clay)
syste
mYo
ungrsquo
s mod
ulus
(Nm
m2)
and
(PEO
+PM
MA+
clay)
for (
PEO+
PMM
A)
Youn
grsquo
Figure 12 Variations of Youngrsquos modulus for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
concentrations the polymers exist in agglomeration and theclay is not well dispersed The overall result is the increasein the ductility of the composite material with increasingsalt concentration The net increase in elongation at breakfor PCS system suggests filler induced dimensional stabilityto the composite electrolyte films making them capable ofsustaining and withstanding any external pressureshock to abetter level
36 Youngrsquos Modulus of PEOLiClO4CPMMT Composites
Youngrsquos modulus is a variable that describes the relationshipof stress to strain within the elastic region This is measuredfrom the slope of the curve within the elastic area of thespecimen The modulus of elasticity describes a materialrsquosstiffness the greater the modulus the stiffer the material Itquantifies the elasticity of the polymerIt is truly associatedwith primary and secondary chemical bonds Unlike the neatpolymer where the mechanical properties are determinedalmost entirely by matrix the mechanical properties of thecomposite depend on the interaction between the polymerand the added fillers From Figure 12 it is clear that Youngrsquosmodulus of the composites electrolyte decreases with theincreasing concentration of inorganic contents at constantclay levelThe influence of LiClO
4on the mechanical proper-
ties of PEOCPMMT film resembles the plasticization effectThe interaction between PEO and CPMMT is weakened bythe increasing content of salt The same behavior of Youngrsquosmodulus with filler has been reported earlier in the literature[29] As mechanical properties change by changing thecomposition of components as well as with the applied forcethey are difficult to analyze Also this decrease may probablybe explained in terms of debonding around polymer andclay interphases and void formation It can be concluded thatvalue of modulus depends highly on the distribution of fillerparticles in the polymer matrix which in turn depends on
International Journal of Polymer Science 9
the particleparticle interaction (agglomeration) andpolymerparticle interaction (adhesion and wetting) and morphologyof the filler particles [30]
37 Elongations at Break of PEOPMMALiClO4CPMMTBlend Composites System In order to have a more clear ideaof the change inmechanical properties of the blend compositesystem first the addition of salt to the blend system wasstudied for its effect on the mechanical properties and thenCPMMT was added to the same system and the sampleswere analyzed by UTM From the results given in Figure 11it is clear that elongation at break decreases initially withthe increasing concentration of salt to the blend system andthen starts increasing with higher salt concentration Thisdecrease in failure strain is due to the rigid filler additionwhich restricts the mobility of the PEO polymermolecules toflow freely past one another thus causing premature failureThe original elasticity of PEO is distorted due to the additionof PMMA and LiClO
4which is in close agreement with the
conclusion that the addition of rigid particles like PMMAinto the polymer matrix increases its stiffness and toughness[31 32] Compositeswith these properties can be used for heatresistant materials or product packaging materials
38 Youngrsquos Modulus of PEOPMMALiClO4CPMM Blend
Composites System Youngrsquos modulus of the PEOPMMA asa function of salt is shown in Figure 12 From this Figure itis clear that Youngrsquos modulus of the blend composite showsan overall decrease with the addition of salt This decreaseshows the weaker PEO interchain interaction and increasein the particle size of the inorganic phase because of localaggregations of particles in the presence of PMMA thesephenomenamay act as flaws in it [33 34]The same trend hasbeen confirmed by the SEM result as well This means thatthe addition of salt to the PEOPMMA composite suppressesthematerialrsquos stiffness and hence elasticity of the polymer Butwhen clay was added to the same PEOPMMASalt systeman enormous increase in the value of Young modulus wasobserved as shown in Figure 12 This is due to the interca-lation of polymer chains within the clay galleries that avoidsegmental motion of the polymer chains [35] Although thereis an overall decrease in the value of Young modulus of thePEOPMMALiClO
4CPMMT system with increasing salt
concentration still it is much higher than that of the virgin(neat) poly(ethylene oxide) (PEO) and PEOSaltCPMMTThis is in close agreement with the conclusion that theaddition of rigid particles like PMMA into the polymermatrix increases its stiffness [31]
4 Conclusions
This work used cetylpyridinium chloride to modify MMTmixed with higher molecular weight PEOLiClO
4and
PEOPMMALiClO4to produce composite materials The
experimental results showed that at constant salt contentthe addition of CPMMT first reduces crystallinity of PEOtill 33 wt of clay and then starts increasing at higher claycontent Thus 33 wt of clay was selected as the optimum
clay loadings for composites fabrication The XRD resultsshowed that the crystallinity of composites at optimum clayloading increases with increasing salt content and ionicconductivity obtained from impedance technique showeddeclining trend with higher salt content The addition of50wt of higher molecular weight PMMA to the com-posite of PEOSaltCPMMT affected the properties due tothe immiscibility or aggregation of filler within the poly-mer matrix however the blend composites showed bettermechanical performanceThe composite of PEOwith 35 wtof salt and 33 wt of CPMMT exhibited better performance
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] S Sultana Fabrication and studies on thin film composites ofPoly (Ethylene Oxide) [PhD thesis] University of PeshawarPeshawar Pakistan 2013
[2] T Lan P D Kaviratna and T J Pinnavaia ldquoEpoxy self-polymerization in smectite claysrdquo Journal of Physics and Chem-istry of Solids vol 57 no 6-8 pp 1005ndash1010 1996
[3] X Q Yang H S Lee L Hanson J McBreen and Y OkamotoldquoDevelopment of a new plasticizer for poly(ethylene oxide)-based polymer electrolyte and the investigation of their ion-pairdissociation effectrdquo Journal of Power Sources vol 54 no 2 pp198ndash204 1995
[4] R Mishra and K J Rao ldquoElectrical conductivity studies ofpoly(ethyleneoxide)-poly(vinylalcohol) blendsrdquo Solid State Ion-ics vol 106 no 1-2 pp 113ndash127 1998
[5] M S Khan A Shakoor and J Nisar ldquoConductance study ofpoly(ethylene oxide)- and poly(propylene oxide)-based poly-electrolytesrdquo Ionics vol 16 no 6 pp 539ndash542 2010
[6] Z Shen G P Simon and Y-B Cheng ldquoComparison ofsolution intercalation and melt intercalation of polymer-claynanocompositesrdquo Polymer vol 43 no 15 pp 4251ndash4260 2002
[7] P Aranda and E Ruiz-Hitzky ldquoNew polyelectrolyte materialsbased on smectite polyoxyethylene intercalation compoundsrdquoActa Polymerica vol 45 no 2 pp 59ndash67 1994
[8] D Ratna S Divekar A B Samui B C Chakraborty and AK Banthia ldquoPoly(ethylene oxide)clay nanocomposite thermo-mechanical properties andmorphologyrdquo Polymer vol 47 no 11pp 4068ndash4074 2006
[9] D Ratna S Divekar S Patchaiappan A B Samui and BC Chakraborty ldquoPoly(ethylene oxide)clay nanocomposites forsolid polymer electrolyte applicationsrdquo Polymer Internationalvol 56 no 7 pp 900ndash904 2007
[10] S K Lim JW Kim I Chin Y K Kwon andH J Choi ldquoPrepa-ration and interaction characteristics of organically modifiedmontmorillonite nanocomposite with miscible polymer blendof poly(ethylene oxide) and poly(methyl methacrylate)rdquo Chem-istry of Materials vol 14 no 5 pp 1989ndash1994 2002
[11] Y H Hyun S T Lim H J Choi and M S Jhon ldquoRheologyof poly(ethylene oxide)organoclay nanocompositesrdquo Macro-molecules vol 34 no 23 pp 8084ndash8093 2001
10 International Journal of Polymer Science
[12] H-W Chen C-Y Chiu and F-C Chang ldquoConductivity en-hancement mechanism of the poly(ethylene oxide)modified-clayLiClO
4systemsrdquo Journal of Polymer Science Part B Poly-
mer Physics vol 40 no 13 pp 1342ndash1353 2002[13] S Sultana M S Khan and M Humayun ldquoPreparation mor-
phology and thermal and optical properties of thin films offerric chloridepolyethylene oxide compositesrdquo Turkish Journalof Chemistry vol 36 no 5 pp 709ndash716 2012
[14] R Baskaran S Selvasekarapandian N Kuwata J Kawamuraand T Hattori ldquoConductivity and thermal studies of blendpolymer electrolytes based on PVAc-PMMArdquo Solid State Ionicsvol 177 no 26-32 pp 2679ndash2682 2006
[15] S K Lim S T Lim H B Kim I Chin and H J Choi ldquoPrepa-ration and physical characterization of polyepichlorohydrinelastomerclay nanocompositesrdquo Journal of MacromolecularScience Part B Physics vol 42 no 6 pp 1197ndash1208 2003
[16] B Chen and J R G Evans ldquoPreferential intercalation inpolymer-clay nanocompositesrdquo Journal of Physical Chemistry Bvol 108 no 39 pp 14986ndash14990 2004
[17] B Kumar and L G Scanlon ldquoPolymer-ceramic compositeelectrolytes conductivity and thermal history effectsrdquo SolidState Ionics vol 124 no 3 pp 239ndash254 1999
[18] J-H Chang S J Kim Y L Joo and S Im ldquoPoly(ethyleneterephthalate) nanocomposites by in situ interlayer polymeriza-tion the thermo-mechanical properties and morphology of thehybrid fibersrdquo Polymer vol 45 no 3 pp 919ndash926 2004
[19] X Qian N Gu Z Cheng X Yang E Wang and S DongldquoImpedance study of (PEO)
10LiClO
4-Al2O3composite polymer
electrolyte with blocking electrodesrdquo Electrochimica Acta vol46 no 12 pp 1829ndash1836 2001
[20] G J Brug A L G Van den Eeden M Sluyters-Rehbach and JH Sluyters ldquoThe analysis of electrode impedances complicatedby the presence of a constant phase elementrdquo Journal ofElectroanalytical Chemistry and Interfacial Electrochemistry vol176 no 1-2 pp 275ndash295 1984
[21] F Bellucci M Valentino T Monetta et al ldquoImpedance spec-troscopy of reactive polymers 1rdquo Journal of Polymer SciencePart B Polymer Physics vol 32 no 15 pp 2519ndash2527 1994
[22] J T S Irvine D C Sinclair and A R West ldquoElectroceramicscharacterization by impedance spectroscopyrdquo Advanced Mate-rials vol 2 no 3 pp 132ndash138 1990
[23] K V Kumar and G S Sundari ldquoConductivity studies of(PEO +KHCO
3) solid electrolyte system and its application
as an electrochemical cellrdquo Journal of Engineering Science andTechnology vol 5 no 2 pp 130ndash139 2010
[24] P C Srivastava in Solid State Ionics Materials and ApplicationsB V R Chowdar Ed pp 561ndash565 World Scientific Singapore1992
[25] S Ibrahim and M R Johan ldquoConductivity thermal andneural networkmodel nanocomposite solid polymer electrolytesystem (PEO-LiPF6-EC-CNT)rdquo International Journal of Elec-trochemical Science vol 6 no 11 pp 5565ndash5587 2011
[26] P P Chu M J Reddy and J Tsai ldquoStructural and transportcharacteristics of polyethylene oxidephenolic resin blend solidpolymer electrolytesrdquo Journal of Polymer Science Part B Poly-mer Physics vol 42 no 21 pp 3866ndash3875 2004
[27] H-W Chen C-Y Chiu and F-C Chang ldquoConductivityenhancement mechanism of the poly(ethylene oxide)modi-fied-clayLiClO
4systemsrdquo Journal of Polymer Science Part B
Polymer Physics vol 40 no 13 pp 1342ndash1353 2002
[28] K Jeddi N T Qazvini S H Jafari and H A KhonakdarldquoEnhanced ionic conductivity in PEOPMMA glassy misci-ble blends role of nano-confinement of minority componentchainsrdquo Journal of Polymer Science Part B Polymer Physics vol48 no 19 pp 2065ndash2071 2010
[29] S Ramesh and N B Khoo ldquoConductivity mechanical andthermal studies on poly(methyl methacrylate)-based polymerelectrolytes complexed with lithium tetraborate and propylenecarbonaterdquo Journal of Materials Engineering and Performancevol 21 no 1 pp 89ndash94 2012
[30] F Ali Synthesis and characterization of polyimidesilicabased nano-composites material [MPhil Thesis] University ofPeshawar Peshawar Pakistan 2006
[31] S Bai J Chen Z Huang and Z Yu ldquoThe role of the interfacialstrength in glass bead filled HDPErdquo Journal of Materials ScienceLetters vol 19 no 17 pp 1587ndash1589 2000
[32] G Nasar Synthesis and characterization of poly (vinyl alcohol)composites [MPhil thesis] University of Peshawar PeshawarPakistan 2008
[33] A Bandyopadhyay M de Sarkar and A K BhowmickldquoPoly(vinyl alcohol)silica hybrid nanocomposites by sol-geltechnique synthesis and propertiesrdquo Journal of Materials Sci-ence vol 40 no 19 pp 5233ndash5241 2005
[34] H B Kim J S Choi C H Lee S T Lim M S Jhon andH J Choi ldquoPolymer blendorganoclay nanocomposite withpoly(ethylene oxide) and poly(methylmethacrylate)rdquo EuropeanPolymer Journal vol 41 no 4 pp 679ndash685 2005
[35] R L Ledoux and J L White ldquoInfra red studies of hydrogenbonding interaction between kaolinite surfaces and intercalatedpotassium acetate hydrazine formamide and ureardquo Journal ofColloid and Interface Science vol 21 pp 27ndash52 1996
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
6 International Journal of Polymer Science
(A)
(B)
(C)
(D)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 6 Combined XRD pattern of PEOSalt composite systemwith 198 (A) 33 (B) 462 (C) and 594 (D) wt of CPMMT
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 7 Combined XRD scans of PEOCPMMTSalt (PCS1)(21 wt A) PEOCPMMTSalt (PCS2) (35 wt B) and PEOCPMMTSalt (PCS3) (5 wt C)
The value of ionic conductivity obtained at room tem-perature (15∘C) for pure poly(ethylene oxide) (PEO) is lessthan 678 times 10minus10 S cmminus1 reported in the literature earlier byKumar and coworker [17] for the samemolecular weight PEOat 30∘C This difference in conductivity values is because ofthe temperature and changing nature of solvent used in ourstudy [23] From the table given as inset in Figure 10 it isclear that the conductivity of PEO at laboratory temperaturethat is 15∘C increases sharplywith the salt incorporationThe
(A)
(B)
(C)
Inte
nsity
(CPS
)
20 30 40 50 60 70
2120579 (∘)
Figure 8 Combined XRD scans of PEOPMMACPMMTSalt(PPCS1) (21 wt A) PEOPMMACPMMTSalt (PPCS2) (35 wtB) and PEOPMMACPMMTSalt (PPCS3) (5 wt C)
same trend in conductivity of PEO based electrolytes withthe salt concentration has also been observed by Srivastavaand Ibrahim et al [24 25] This increase is due to theincrease in charge carriers caused by the addition of higherconcentration of LiClO
4and the increase in the fraction of
amorphous phaseThe addition of ionic salt decreases degra-dation temperature because of the growth of amorphous frac-tion and destabilizes the polymer network The PEOLiClO
4
electrolyte with high salt concentration was found to be lessstable Alternatively CPMMT was used to overcome thesedrawbacks Inorganic fillers are usually used to improvethe electrochemical and mechanical properties [26] Clay isinorganic filler with intercalation property where clay layersmaintain their registry Intercalating polymer (residing poly-mer chains between silicates) in a layered clay host can pro-duce huge interfacial area to sustain the mechanical propertyof polymer electrolyte system and impart salt solvating powerto dissolve the lithium salt [27] A glance at Figure 10 and insettable reveals that the addition of salt at constant (33 wt)clay content increases the conductivity of PEOSaltCPMMT(PCS) composites retaining dimensional stability till PCS2(35 wt) beyond PCS2 further addition of salt decreases theconductivity badlyThis initial increase is due to the decreasein the crystallinity and increase in amorphous fraction ofPEO for ion conduction till equilibrium is achieved at PCS2This is consistent with our XRD results The conductivitydecreases drastically when amount of salt increases fromPCS2 to PCS3 (5wt) but is still higher than that of pristinepolymer The possible explanation for this behavior may beion association and the formation of charge multipliers [25]In order to study the effect of poly(methyl methacrylate)(PMMA) incorporation on the ionic conductivity of PEObased solid polymer electrolytes PMMA was blended with
International Journal of Polymer Science 7
1e6 2e6 3e6 4e600
minus1e6
minus2e6
minus3e6
minus4e6
Z998400
PEOLiClO4
N998400998400
(a)
Samples PS PCS PPCS661410 169520
CPE1-TCPE1-P 0922 09848 0535CPE2-TCPE2-P 0864 0715 08156
50000 100000 15000000
minus50000
minus100000
minus150000
Z998400
R1Ω 127 times 106
965 times 10minus11
544 times 10minus11
622 times 10minus11
946 times 10minus9
882 times 10minus9
877 times 10minus10
CPE1CPE2 CPE2R1
N998400998400
(b)
1e6 2e6 3e6 5e64e60
Z998400
0
minus1e6
minus2e6
minus3e6
minus5e6
minus4e6
PEOCPMMTLiClO4
N998400998400
(c)
1e7 2e7 3e70
Z998400
0
minus1e7
minus2e7
minus3e7PEOPMMACPMMTLiClO4
N998400998400
(d)
Figure 9 Typical Nyquist impedance plots for PEOSalt (PS) (a) PEOSalt (PS) after fitting to equivalent circuit (b) Inset showing thatdiagram of circuit and extracted parameters for the circuit elements of PS PCS and PPCS are summarized in the table PEOSaltCPMMT(PCS) (c) PEOPMMASaltCPMMT (PPCS) (d)
PEO for solid polymer electrolyte (SPE) composites Fromthe values of ionic conductivity given in Figure 10 and insettable it is clear that the addition of PMMA to PEOSaltelectrolyte system decreases the conductivity of PCS systembut still shows higher value than pure PEO films The rigidstructure of PMMA due to the entrapped silicate layersalters the segmental dynamics of PEO so there is decreasein conductivity Jeddi and coworkers [28] have reported anoverlapweight fraction for PEOPMMAblendwhich is about28 wt for PEO Overlap weight fraction is that weight atwhich PEO starts interpenetration and miscibility of blendsis affected In our system the amount of PEO is far more thanoverlap weight fraction So it causes decrease in conductivityand an increase in the agglomeration of clay by decreasing itsinteraction with the PEOThe same trend has been observed
in mechanical properties of the PEOPMMASaltCPMMT(PPCS) composites The values of ionic conductivity wereached at laboratory temperature of 15∘C are higher thanthose reported for the PEOPMMAsaltNa-MMT in theliterature at 25∘C [22] This increase may be caused by thebetter dispersion of CPMMT
35 Elongation at Break of PEOLiClO4CPMMT Composite
System Elongation at break is the strain at failure or percentchange at failure and explains the ductility of the materialwith external forceThe effect of salt addition on the ductilityor elongation is shown in Figure 11 The result fromFigure 11 depicts that ductility of the composite materialincreases with increasing salt concentration in the resultingcomposites This increase is attributed to the presence of
8 International Journal of Polymer Science
0 1 2 3 4 5 6
PPSCPSC
Salt concentration (wt)
Film codeP0PCPCS1PCS2PCS3PPCS1PPCS2PPCS3
minus1
minus7
minus8
minus9
minus10
minus11
minus12
726 times 10minus12
1017 times 10minus7
5 times 10minus10
294 times 10minus8
556 times 10minus11
220 times 10minus10
424 times 10minus9
331 times 10minus9
Bulk 120590 (Scm)
Log120590
(S cm
minus1)
Figure 10 Bulk ionic conductivity variation for PSC and PPSCwithweight of salt for composite system at room temperature (15∘C)
0
100
200
300
400
500
600
0
5
10
15
20
25
0 1 2 3 4 5 6Salt concentration (wt)
minus1
Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
clay)
syste
m
and
(PEO
+PM
MA+
clay)
PEO + clay
PEO + PMMA
PEO + PMMA + clay Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
PMM
A)
Figure 11 Variation of elongation at break for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
CPMMT which enhances the mobility of the PEO polymerThe highest elongation at break is obtained for the PCS2composite and beyond PCS2 elongation at break decreasesThe higher uniformity in the dispersion of salt and claywithin PEO is correlated with better adhesion between thecomponents of the composite due to the homogeneousdispersion of CPCMMT at PCS2 composition The decreasein the ductility beyond PCS2 is due to the restriction inchain mobility of the matrix and the filler particles acting asdefect points [29] This also shows that beyond certain limitof salt concentration the behavior changes Further at higher
20
40
60
80
100
120
140
160
0
200
400
600
800
1000
0 1 2 3 4 5 6Salt concentration (wt)
PEO + clay
PEO + PMMA
PEO + PMMA + clay
minus1
s mod
ulus
(Nm
m2) f
or (P
EO+
clay)
syste
mYo
ungrsquo
s mod
ulus
(Nm
m2)
and
(PEO
+PM
MA+
clay)
for (
PEO+
PMM
A)
Youn
grsquo
Figure 12 Variations of Youngrsquos modulus for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
concentrations the polymers exist in agglomeration and theclay is not well dispersed The overall result is the increasein the ductility of the composite material with increasingsalt concentration The net increase in elongation at breakfor PCS system suggests filler induced dimensional stabilityto the composite electrolyte films making them capable ofsustaining and withstanding any external pressureshock to abetter level
36 Youngrsquos Modulus of PEOLiClO4CPMMT Composites
Youngrsquos modulus is a variable that describes the relationshipof stress to strain within the elastic region This is measuredfrom the slope of the curve within the elastic area of thespecimen The modulus of elasticity describes a materialrsquosstiffness the greater the modulus the stiffer the material Itquantifies the elasticity of the polymerIt is truly associatedwith primary and secondary chemical bonds Unlike the neatpolymer where the mechanical properties are determinedalmost entirely by matrix the mechanical properties of thecomposite depend on the interaction between the polymerand the added fillers From Figure 12 it is clear that Youngrsquosmodulus of the composites electrolyte decreases with theincreasing concentration of inorganic contents at constantclay levelThe influence of LiClO
4on the mechanical proper-
ties of PEOCPMMT film resembles the plasticization effectThe interaction between PEO and CPMMT is weakened bythe increasing content of salt The same behavior of Youngrsquosmodulus with filler has been reported earlier in the literature[29] As mechanical properties change by changing thecomposition of components as well as with the applied forcethey are difficult to analyze Also this decrease may probablybe explained in terms of debonding around polymer andclay interphases and void formation It can be concluded thatvalue of modulus depends highly on the distribution of fillerparticles in the polymer matrix which in turn depends on
International Journal of Polymer Science 9
the particleparticle interaction (agglomeration) andpolymerparticle interaction (adhesion and wetting) and morphologyof the filler particles [30]
37 Elongations at Break of PEOPMMALiClO4CPMMTBlend Composites System In order to have a more clear ideaof the change inmechanical properties of the blend compositesystem first the addition of salt to the blend system wasstudied for its effect on the mechanical properties and thenCPMMT was added to the same system and the sampleswere analyzed by UTM From the results given in Figure 11it is clear that elongation at break decreases initially withthe increasing concentration of salt to the blend system andthen starts increasing with higher salt concentration Thisdecrease in failure strain is due to the rigid filler additionwhich restricts the mobility of the PEO polymermolecules toflow freely past one another thus causing premature failureThe original elasticity of PEO is distorted due to the additionof PMMA and LiClO
4which is in close agreement with the
conclusion that the addition of rigid particles like PMMAinto the polymer matrix increases its stiffness and toughness[31 32] Compositeswith these properties can be used for heatresistant materials or product packaging materials
38 Youngrsquos Modulus of PEOPMMALiClO4CPMM Blend
Composites System Youngrsquos modulus of the PEOPMMA asa function of salt is shown in Figure 12 From this Figure itis clear that Youngrsquos modulus of the blend composite showsan overall decrease with the addition of salt This decreaseshows the weaker PEO interchain interaction and increasein the particle size of the inorganic phase because of localaggregations of particles in the presence of PMMA thesephenomenamay act as flaws in it [33 34]The same trend hasbeen confirmed by the SEM result as well This means thatthe addition of salt to the PEOPMMA composite suppressesthematerialrsquos stiffness and hence elasticity of the polymer Butwhen clay was added to the same PEOPMMASalt systeman enormous increase in the value of Young modulus wasobserved as shown in Figure 12 This is due to the interca-lation of polymer chains within the clay galleries that avoidsegmental motion of the polymer chains [35] Although thereis an overall decrease in the value of Young modulus of thePEOPMMALiClO
4CPMMT system with increasing salt
concentration still it is much higher than that of the virgin(neat) poly(ethylene oxide) (PEO) and PEOSaltCPMMTThis is in close agreement with the conclusion that theaddition of rigid particles like PMMA into the polymermatrix increases its stiffness [31]
4 Conclusions
This work used cetylpyridinium chloride to modify MMTmixed with higher molecular weight PEOLiClO
4and
PEOPMMALiClO4to produce composite materials The
experimental results showed that at constant salt contentthe addition of CPMMT first reduces crystallinity of PEOtill 33 wt of clay and then starts increasing at higher claycontent Thus 33 wt of clay was selected as the optimum
clay loadings for composites fabrication The XRD resultsshowed that the crystallinity of composites at optimum clayloading increases with increasing salt content and ionicconductivity obtained from impedance technique showeddeclining trend with higher salt content The addition of50wt of higher molecular weight PMMA to the com-posite of PEOSaltCPMMT affected the properties due tothe immiscibility or aggregation of filler within the poly-mer matrix however the blend composites showed bettermechanical performanceThe composite of PEOwith 35 wtof salt and 33 wt of CPMMT exhibited better performance
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] S Sultana Fabrication and studies on thin film composites ofPoly (Ethylene Oxide) [PhD thesis] University of PeshawarPeshawar Pakistan 2013
[2] T Lan P D Kaviratna and T J Pinnavaia ldquoEpoxy self-polymerization in smectite claysrdquo Journal of Physics and Chem-istry of Solids vol 57 no 6-8 pp 1005ndash1010 1996
[3] X Q Yang H S Lee L Hanson J McBreen and Y OkamotoldquoDevelopment of a new plasticizer for poly(ethylene oxide)-based polymer electrolyte and the investigation of their ion-pairdissociation effectrdquo Journal of Power Sources vol 54 no 2 pp198ndash204 1995
[4] R Mishra and K J Rao ldquoElectrical conductivity studies ofpoly(ethyleneoxide)-poly(vinylalcohol) blendsrdquo Solid State Ion-ics vol 106 no 1-2 pp 113ndash127 1998
[5] M S Khan A Shakoor and J Nisar ldquoConductance study ofpoly(ethylene oxide)- and poly(propylene oxide)-based poly-electrolytesrdquo Ionics vol 16 no 6 pp 539ndash542 2010
[6] Z Shen G P Simon and Y-B Cheng ldquoComparison ofsolution intercalation and melt intercalation of polymer-claynanocompositesrdquo Polymer vol 43 no 15 pp 4251ndash4260 2002
[7] P Aranda and E Ruiz-Hitzky ldquoNew polyelectrolyte materialsbased on smectite polyoxyethylene intercalation compoundsrdquoActa Polymerica vol 45 no 2 pp 59ndash67 1994
[8] D Ratna S Divekar A B Samui B C Chakraborty and AK Banthia ldquoPoly(ethylene oxide)clay nanocomposite thermo-mechanical properties andmorphologyrdquo Polymer vol 47 no 11pp 4068ndash4074 2006
[9] D Ratna S Divekar S Patchaiappan A B Samui and BC Chakraborty ldquoPoly(ethylene oxide)clay nanocomposites forsolid polymer electrolyte applicationsrdquo Polymer Internationalvol 56 no 7 pp 900ndash904 2007
[10] S K Lim JW Kim I Chin Y K Kwon andH J Choi ldquoPrepa-ration and interaction characteristics of organically modifiedmontmorillonite nanocomposite with miscible polymer blendof poly(ethylene oxide) and poly(methyl methacrylate)rdquo Chem-istry of Materials vol 14 no 5 pp 1989ndash1994 2002
[11] Y H Hyun S T Lim H J Choi and M S Jhon ldquoRheologyof poly(ethylene oxide)organoclay nanocompositesrdquo Macro-molecules vol 34 no 23 pp 8084ndash8093 2001
10 International Journal of Polymer Science
[12] H-W Chen C-Y Chiu and F-C Chang ldquoConductivity en-hancement mechanism of the poly(ethylene oxide)modified-clayLiClO
4systemsrdquo Journal of Polymer Science Part B Poly-
mer Physics vol 40 no 13 pp 1342ndash1353 2002[13] S Sultana M S Khan and M Humayun ldquoPreparation mor-
phology and thermal and optical properties of thin films offerric chloridepolyethylene oxide compositesrdquo Turkish Journalof Chemistry vol 36 no 5 pp 709ndash716 2012
[14] R Baskaran S Selvasekarapandian N Kuwata J Kawamuraand T Hattori ldquoConductivity and thermal studies of blendpolymer electrolytes based on PVAc-PMMArdquo Solid State Ionicsvol 177 no 26-32 pp 2679ndash2682 2006
[15] S K Lim S T Lim H B Kim I Chin and H J Choi ldquoPrepa-ration and physical characterization of polyepichlorohydrinelastomerclay nanocompositesrdquo Journal of MacromolecularScience Part B Physics vol 42 no 6 pp 1197ndash1208 2003
[16] B Chen and J R G Evans ldquoPreferential intercalation inpolymer-clay nanocompositesrdquo Journal of Physical Chemistry Bvol 108 no 39 pp 14986ndash14990 2004
[17] B Kumar and L G Scanlon ldquoPolymer-ceramic compositeelectrolytes conductivity and thermal history effectsrdquo SolidState Ionics vol 124 no 3 pp 239ndash254 1999
[18] J-H Chang S J Kim Y L Joo and S Im ldquoPoly(ethyleneterephthalate) nanocomposites by in situ interlayer polymeriza-tion the thermo-mechanical properties and morphology of thehybrid fibersrdquo Polymer vol 45 no 3 pp 919ndash926 2004
[19] X Qian N Gu Z Cheng X Yang E Wang and S DongldquoImpedance study of (PEO)
10LiClO
4-Al2O3composite polymer
electrolyte with blocking electrodesrdquo Electrochimica Acta vol46 no 12 pp 1829ndash1836 2001
[20] G J Brug A L G Van den Eeden M Sluyters-Rehbach and JH Sluyters ldquoThe analysis of electrode impedances complicatedby the presence of a constant phase elementrdquo Journal ofElectroanalytical Chemistry and Interfacial Electrochemistry vol176 no 1-2 pp 275ndash295 1984
[21] F Bellucci M Valentino T Monetta et al ldquoImpedance spec-troscopy of reactive polymers 1rdquo Journal of Polymer SciencePart B Polymer Physics vol 32 no 15 pp 2519ndash2527 1994
[22] J T S Irvine D C Sinclair and A R West ldquoElectroceramicscharacterization by impedance spectroscopyrdquo Advanced Mate-rials vol 2 no 3 pp 132ndash138 1990
[23] K V Kumar and G S Sundari ldquoConductivity studies of(PEO +KHCO
3) solid electrolyte system and its application
as an electrochemical cellrdquo Journal of Engineering Science andTechnology vol 5 no 2 pp 130ndash139 2010
[24] P C Srivastava in Solid State Ionics Materials and ApplicationsB V R Chowdar Ed pp 561ndash565 World Scientific Singapore1992
[25] S Ibrahim and M R Johan ldquoConductivity thermal andneural networkmodel nanocomposite solid polymer electrolytesystem (PEO-LiPF6-EC-CNT)rdquo International Journal of Elec-trochemical Science vol 6 no 11 pp 5565ndash5587 2011
[26] P P Chu M J Reddy and J Tsai ldquoStructural and transportcharacteristics of polyethylene oxidephenolic resin blend solidpolymer electrolytesrdquo Journal of Polymer Science Part B Poly-mer Physics vol 42 no 21 pp 3866ndash3875 2004
[27] H-W Chen C-Y Chiu and F-C Chang ldquoConductivityenhancement mechanism of the poly(ethylene oxide)modi-fied-clayLiClO
4systemsrdquo Journal of Polymer Science Part B
Polymer Physics vol 40 no 13 pp 1342ndash1353 2002
[28] K Jeddi N T Qazvini S H Jafari and H A KhonakdarldquoEnhanced ionic conductivity in PEOPMMA glassy misci-ble blends role of nano-confinement of minority componentchainsrdquo Journal of Polymer Science Part B Polymer Physics vol48 no 19 pp 2065ndash2071 2010
[29] S Ramesh and N B Khoo ldquoConductivity mechanical andthermal studies on poly(methyl methacrylate)-based polymerelectrolytes complexed with lithium tetraborate and propylenecarbonaterdquo Journal of Materials Engineering and Performancevol 21 no 1 pp 89ndash94 2012
[30] F Ali Synthesis and characterization of polyimidesilicabased nano-composites material [MPhil Thesis] University ofPeshawar Peshawar Pakistan 2006
[31] S Bai J Chen Z Huang and Z Yu ldquoThe role of the interfacialstrength in glass bead filled HDPErdquo Journal of Materials ScienceLetters vol 19 no 17 pp 1587ndash1589 2000
[32] G Nasar Synthesis and characterization of poly (vinyl alcohol)composites [MPhil thesis] University of Peshawar PeshawarPakistan 2008
[33] A Bandyopadhyay M de Sarkar and A K BhowmickldquoPoly(vinyl alcohol)silica hybrid nanocomposites by sol-geltechnique synthesis and propertiesrdquo Journal of Materials Sci-ence vol 40 no 19 pp 5233ndash5241 2005
[34] H B Kim J S Choi C H Lee S T Lim M S Jhon andH J Choi ldquoPolymer blendorganoclay nanocomposite withpoly(ethylene oxide) and poly(methylmethacrylate)rdquo EuropeanPolymer Journal vol 41 no 4 pp 679ndash685 2005
[35] R L Ledoux and J L White ldquoInfra red studies of hydrogenbonding interaction between kaolinite surfaces and intercalatedpotassium acetate hydrazine formamide and ureardquo Journal ofColloid and Interface Science vol 21 pp 27ndash52 1996
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
International Journal of Polymer Science 7
1e6 2e6 3e6 4e600
minus1e6
minus2e6
minus3e6
minus4e6
Z998400
PEOLiClO4
N998400998400
(a)
Samples PS PCS PPCS661410 169520
CPE1-TCPE1-P 0922 09848 0535CPE2-TCPE2-P 0864 0715 08156
50000 100000 15000000
minus50000
minus100000
minus150000
Z998400
R1Ω 127 times 106
965 times 10minus11
544 times 10minus11
622 times 10minus11
946 times 10minus9
882 times 10minus9
877 times 10minus10
CPE1CPE2 CPE2R1
N998400998400
(b)
1e6 2e6 3e6 5e64e60
Z998400
0
minus1e6
minus2e6
minus3e6
minus5e6
minus4e6
PEOCPMMTLiClO4
N998400998400
(c)
1e7 2e7 3e70
Z998400
0
minus1e7
minus2e7
minus3e7PEOPMMACPMMTLiClO4
N998400998400
(d)
Figure 9 Typical Nyquist impedance plots for PEOSalt (PS) (a) PEOSalt (PS) after fitting to equivalent circuit (b) Inset showing thatdiagram of circuit and extracted parameters for the circuit elements of PS PCS and PPCS are summarized in the table PEOSaltCPMMT(PCS) (c) PEOPMMASaltCPMMT (PPCS) (d)
PEO for solid polymer electrolyte (SPE) composites Fromthe values of ionic conductivity given in Figure 10 and insettable it is clear that the addition of PMMA to PEOSaltelectrolyte system decreases the conductivity of PCS systembut still shows higher value than pure PEO films The rigidstructure of PMMA due to the entrapped silicate layersalters the segmental dynamics of PEO so there is decreasein conductivity Jeddi and coworkers [28] have reported anoverlapweight fraction for PEOPMMAblendwhich is about28 wt for PEO Overlap weight fraction is that weight atwhich PEO starts interpenetration and miscibility of blendsis affected In our system the amount of PEO is far more thanoverlap weight fraction So it causes decrease in conductivityand an increase in the agglomeration of clay by decreasing itsinteraction with the PEOThe same trend has been observed
in mechanical properties of the PEOPMMASaltCPMMT(PPCS) composites The values of ionic conductivity wereached at laboratory temperature of 15∘C are higher thanthose reported for the PEOPMMAsaltNa-MMT in theliterature at 25∘C [22] This increase may be caused by thebetter dispersion of CPMMT
35 Elongation at Break of PEOLiClO4CPMMT Composite
System Elongation at break is the strain at failure or percentchange at failure and explains the ductility of the materialwith external forceThe effect of salt addition on the ductilityor elongation is shown in Figure 11 The result fromFigure 11 depicts that ductility of the composite materialincreases with increasing salt concentration in the resultingcomposites This increase is attributed to the presence of
8 International Journal of Polymer Science
0 1 2 3 4 5 6
PPSCPSC
Salt concentration (wt)
Film codeP0PCPCS1PCS2PCS3PPCS1PPCS2PPCS3
minus1
minus7
minus8
minus9
minus10
minus11
minus12
726 times 10minus12
1017 times 10minus7
5 times 10minus10
294 times 10minus8
556 times 10minus11
220 times 10minus10
424 times 10minus9
331 times 10minus9
Bulk 120590 (Scm)
Log120590
(S cm
minus1)
Figure 10 Bulk ionic conductivity variation for PSC and PPSCwithweight of salt for composite system at room temperature (15∘C)
0
100
200
300
400
500
600
0
5
10
15
20
25
0 1 2 3 4 5 6Salt concentration (wt)
minus1
Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
clay)
syste
m
and
(PEO
+PM
MA+
clay)
PEO + clay
PEO + PMMA
PEO + PMMA + clay Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
PMM
A)
Figure 11 Variation of elongation at break for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
CPMMT which enhances the mobility of the PEO polymerThe highest elongation at break is obtained for the PCS2composite and beyond PCS2 elongation at break decreasesThe higher uniformity in the dispersion of salt and claywithin PEO is correlated with better adhesion between thecomponents of the composite due to the homogeneousdispersion of CPCMMT at PCS2 composition The decreasein the ductility beyond PCS2 is due to the restriction inchain mobility of the matrix and the filler particles acting asdefect points [29] This also shows that beyond certain limitof salt concentration the behavior changes Further at higher
20
40
60
80
100
120
140
160
0
200
400
600
800
1000
0 1 2 3 4 5 6Salt concentration (wt)
PEO + clay
PEO + PMMA
PEO + PMMA + clay
minus1
s mod
ulus
(Nm
m2) f
or (P
EO+
clay)
syste
mYo
ungrsquo
s mod
ulus
(Nm
m2)
and
(PEO
+PM
MA+
clay)
for (
PEO+
PMM
A)
Youn
grsquo
Figure 12 Variations of Youngrsquos modulus for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
concentrations the polymers exist in agglomeration and theclay is not well dispersed The overall result is the increasein the ductility of the composite material with increasingsalt concentration The net increase in elongation at breakfor PCS system suggests filler induced dimensional stabilityto the composite electrolyte films making them capable ofsustaining and withstanding any external pressureshock to abetter level
36 Youngrsquos Modulus of PEOLiClO4CPMMT Composites
Youngrsquos modulus is a variable that describes the relationshipof stress to strain within the elastic region This is measuredfrom the slope of the curve within the elastic area of thespecimen The modulus of elasticity describes a materialrsquosstiffness the greater the modulus the stiffer the material Itquantifies the elasticity of the polymerIt is truly associatedwith primary and secondary chemical bonds Unlike the neatpolymer where the mechanical properties are determinedalmost entirely by matrix the mechanical properties of thecomposite depend on the interaction between the polymerand the added fillers From Figure 12 it is clear that Youngrsquosmodulus of the composites electrolyte decreases with theincreasing concentration of inorganic contents at constantclay levelThe influence of LiClO
4on the mechanical proper-
ties of PEOCPMMT film resembles the plasticization effectThe interaction between PEO and CPMMT is weakened bythe increasing content of salt The same behavior of Youngrsquosmodulus with filler has been reported earlier in the literature[29] As mechanical properties change by changing thecomposition of components as well as with the applied forcethey are difficult to analyze Also this decrease may probablybe explained in terms of debonding around polymer andclay interphases and void formation It can be concluded thatvalue of modulus depends highly on the distribution of fillerparticles in the polymer matrix which in turn depends on
International Journal of Polymer Science 9
the particleparticle interaction (agglomeration) andpolymerparticle interaction (adhesion and wetting) and morphologyof the filler particles [30]
37 Elongations at Break of PEOPMMALiClO4CPMMTBlend Composites System In order to have a more clear ideaof the change inmechanical properties of the blend compositesystem first the addition of salt to the blend system wasstudied for its effect on the mechanical properties and thenCPMMT was added to the same system and the sampleswere analyzed by UTM From the results given in Figure 11it is clear that elongation at break decreases initially withthe increasing concentration of salt to the blend system andthen starts increasing with higher salt concentration Thisdecrease in failure strain is due to the rigid filler additionwhich restricts the mobility of the PEO polymermolecules toflow freely past one another thus causing premature failureThe original elasticity of PEO is distorted due to the additionof PMMA and LiClO
4which is in close agreement with the
conclusion that the addition of rigid particles like PMMAinto the polymer matrix increases its stiffness and toughness[31 32] Compositeswith these properties can be used for heatresistant materials or product packaging materials
38 Youngrsquos Modulus of PEOPMMALiClO4CPMM Blend
Composites System Youngrsquos modulus of the PEOPMMA asa function of salt is shown in Figure 12 From this Figure itis clear that Youngrsquos modulus of the blend composite showsan overall decrease with the addition of salt This decreaseshows the weaker PEO interchain interaction and increasein the particle size of the inorganic phase because of localaggregations of particles in the presence of PMMA thesephenomenamay act as flaws in it [33 34]The same trend hasbeen confirmed by the SEM result as well This means thatthe addition of salt to the PEOPMMA composite suppressesthematerialrsquos stiffness and hence elasticity of the polymer Butwhen clay was added to the same PEOPMMASalt systeman enormous increase in the value of Young modulus wasobserved as shown in Figure 12 This is due to the interca-lation of polymer chains within the clay galleries that avoidsegmental motion of the polymer chains [35] Although thereis an overall decrease in the value of Young modulus of thePEOPMMALiClO
4CPMMT system with increasing salt
concentration still it is much higher than that of the virgin(neat) poly(ethylene oxide) (PEO) and PEOSaltCPMMTThis is in close agreement with the conclusion that theaddition of rigid particles like PMMA into the polymermatrix increases its stiffness [31]
4 Conclusions
This work used cetylpyridinium chloride to modify MMTmixed with higher molecular weight PEOLiClO
4and
PEOPMMALiClO4to produce composite materials The
experimental results showed that at constant salt contentthe addition of CPMMT first reduces crystallinity of PEOtill 33 wt of clay and then starts increasing at higher claycontent Thus 33 wt of clay was selected as the optimum
clay loadings for composites fabrication The XRD resultsshowed that the crystallinity of composites at optimum clayloading increases with increasing salt content and ionicconductivity obtained from impedance technique showeddeclining trend with higher salt content The addition of50wt of higher molecular weight PMMA to the com-posite of PEOSaltCPMMT affected the properties due tothe immiscibility or aggregation of filler within the poly-mer matrix however the blend composites showed bettermechanical performanceThe composite of PEOwith 35 wtof salt and 33 wt of CPMMT exhibited better performance
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] S Sultana Fabrication and studies on thin film composites ofPoly (Ethylene Oxide) [PhD thesis] University of PeshawarPeshawar Pakistan 2013
[2] T Lan P D Kaviratna and T J Pinnavaia ldquoEpoxy self-polymerization in smectite claysrdquo Journal of Physics and Chem-istry of Solids vol 57 no 6-8 pp 1005ndash1010 1996
[3] X Q Yang H S Lee L Hanson J McBreen and Y OkamotoldquoDevelopment of a new plasticizer for poly(ethylene oxide)-based polymer electrolyte and the investigation of their ion-pairdissociation effectrdquo Journal of Power Sources vol 54 no 2 pp198ndash204 1995
[4] R Mishra and K J Rao ldquoElectrical conductivity studies ofpoly(ethyleneoxide)-poly(vinylalcohol) blendsrdquo Solid State Ion-ics vol 106 no 1-2 pp 113ndash127 1998
[5] M S Khan A Shakoor and J Nisar ldquoConductance study ofpoly(ethylene oxide)- and poly(propylene oxide)-based poly-electrolytesrdquo Ionics vol 16 no 6 pp 539ndash542 2010
[6] Z Shen G P Simon and Y-B Cheng ldquoComparison ofsolution intercalation and melt intercalation of polymer-claynanocompositesrdquo Polymer vol 43 no 15 pp 4251ndash4260 2002
[7] P Aranda and E Ruiz-Hitzky ldquoNew polyelectrolyte materialsbased on smectite polyoxyethylene intercalation compoundsrdquoActa Polymerica vol 45 no 2 pp 59ndash67 1994
[8] D Ratna S Divekar A B Samui B C Chakraborty and AK Banthia ldquoPoly(ethylene oxide)clay nanocomposite thermo-mechanical properties andmorphologyrdquo Polymer vol 47 no 11pp 4068ndash4074 2006
[9] D Ratna S Divekar S Patchaiappan A B Samui and BC Chakraborty ldquoPoly(ethylene oxide)clay nanocomposites forsolid polymer electrolyte applicationsrdquo Polymer Internationalvol 56 no 7 pp 900ndash904 2007
[10] S K Lim JW Kim I Chin Y K Kwon andH J Choi ldquoPrepa-ration and interaction characteristics of organically modifiedmontmorillonite nanocomposite with miscible polymer blendof poly(ethylene oxide) and poly(methyl methacrylate)rdquo Chem-istry of Materials vol 14 no 5 pp 1989ndash1994 2002
[11] Y H Hyun S T Lim H J Choi and M S Jhon ldquoRheologyof poly(ethylene oxide)organoclay nanocompositesrdquo Macro-molecules vol 34 no 23 pp 8084ndash8093 2001
10 International Journal of Polymer Science
[12] H-W Chen C-Y Chiu and F-C Chang ldquoConductivity en-hancement mechanism of the poly(ethylene oxide)modified-clayLiClO
4systemsrdquo Journal of Polymer Science Part B Poly-
mer Physics vol 40 no 13 pp 1342ndash1353 2002[13] S Sultana M S Khan and M Humayun ldquoPreparation mor-
phology and thermal and optical properties of thin films offerric chloridepolyethylene oxide compositesrdquo Turkish Journalof Chemistry vol 36 no 5 pp 709ndash716 2012
[14] R Baskaran S Selvasekarapandian N Kuwata J Kawamuraand T Hattori ldquoConductivity and thermal studies of blendpolymer electrolytes based on PVAc-PMMArdquo Solid State Ionicsvol 177 no 26-32 pp 2679ndash2682 2006
[15] S K Lim S T Lim H B Kim I Chin and H J Choi ldquoPrepa-ration and physical characterization of polyepichlorohydrinelastomerclay nanocompositesrdquo Journal of MacromolecularScience Part B Physics vol 42 no 6 pp 1197ndash1208 2003
[16] B Chen and J R G Evans ldquoPreferential intercalation inpolymer-clay nanocompositesrdquo Journal of Physical Chemistry Bvol 108 no 39 pp 14986ndash14990 2004
[17] B Kumar and L G Scanlon ldquoPolymer-ceramic compositeelectrolytes conductivity and thermal history effectsrdquo SolidState Ionics vol 124 no 3 pp 239ndash254 1999
[18] J-H Chang S J Kim Y L Joo and S Im ldquoPoly(ethyleneterephthalate) nanocomposites by in situ interlayer polymeriza-tion the thermo-mechanical properties and morphology of thehybrid fibersrdquo Polymer vol 45 no 3 pp 919ndash926 2004
[19] X Qian N Gu Z Cheng X Yang E Wang and S DongldquoImpedance study of (PEO)
10LiClO
4-Al2O3composite polymer
electrolyte with blocking electrodesrdquo Electrochimica Acta vol46 no 12 pp 1829ndash1836 2001
[20] G J Brug A L G Van den Eeden M Sluyters-Rehbach and JH Sluyters ldquoThe analysis of electrode impedances complicatedby the presence of a constant phase elementrdquo Journal ofElectroanalytical Chemistry and Interfacial Electrochemistry vol176 no 1-2 pp 275ndash295 1984
[21] F Bellucci M Valentino T Monetta et al ldquoImpedance spec-troscopy of reactive polymers 1rdquo Journal of Polymer SciencePart B Polymer Physics vol 32 no 15 pp 2519ndash2527 1994
[22] J T S Irvine D C Sinclair and A R West ldquoElectroceramicscharacterization by impedance spectroscopyrdquo Advanced Mate-rials vol 2 no 3 pp 132ndash138 1990
[23] K V Kumar and G S Sundari ldquoConductivity studies of(PEO +KHCO
3) solid electrolyte system and its application
as an electrochemical cellrdquo Journal of Engineering Science andTechnology vol 5 no 2 pp 130ndash139 2010
[24] P C Srivastava in Solid State Ionics Materials and ApplicationsB V R Chowdar Ed pp 561ndash565 World Scientific Singapore1992
[25] S Ibrahim and M R Johan ldquoConductivity thermal andneural networkmodel nanocomposite solid polymer electrolytesystem (PEO-LiPF6-EC-CNT)rdquo International Journal of Elec-trochemical Science vol 6 no 11 pp 5565ndash5587 2011
[26] P P Chu M J Reddy and J Tsai ldquoStructural and transportcharacteristics of polyethylene oxidephenolic resin blend solidpolymer electrolytesrdquo Journal of Polymer Science Part B Poly-mer Physics vol 42 no 21 pp 3866ndash3875 2004
[27] H-W Chen C-Y Chiu and F-C Chang ldquoConductivityenhancement mechanism of the poly(ethylene oxide)modi-fied-clayLiClO
4systemsrdquo Journal of Polymer Science Part B
Polymer Physics vol 40 no 13 pp 1342ndash1353 2002
[28] K Jeddi N T Qazvini S H Jafari and H A KhonakdarldquoEnhanced ionic conductivity in PEOPMMA glassy misci-ble blends role of nano-confinement of minority componentchainsrdquo Journal of Polymer Science Part B Polymer Physics vol48 no 19 pp 2065ndash2071 2010
[29] S Ramesh and N B Khoo ldquoConductivity mechanical andthermal studies on poly(methyl methacrylate)-based polymerelectrolytes complexed with lithium tetraborate and propylenecarbonaterdquo Journal of Materials Engineering and Performancevol 21 no 1 pp 89ndash94 2012
[30] F Ali Synthesis and characterization of polyimidesilicabased nano-composites material [MPhil Thesis] University ofPeshawar Peshawar Pakistan 2006
[31] S Bai J Chen Z Huang and Z Yu ldquoThe role of the interfacialstrength in glass bead filled HDPErdquo Journal of Materials ScienceLetters vol 19 no 17 pp 1587ndash1589 2000
[32] G Nasar Synthesis and characterization of poly (vinyl alcohol)composites [MPhil thesis] University of Peshawar PeshawarPakistan 2008
[33] A Bandyopadhyay M de Sarkar and A K BhowmickldquoPoly(vinyl alcohol)silica hybrid nanocomposites by sol-geltechnique synthesis and propertiesrdquo Journal of Materials Sci-ence vol 40 no 19 pp 5233ndash5241 2005
[34] H B Kim J S Choi C H Lee S T Lim M S Jhon andH J Choi ldquoPolymer blendorganoclay nanocomposite withpoly(ethylene oxide) and poly(methylmethacrylate)rdquo EuropeanPolymer Journal vol 41 no 4 pp 679ndash685 2005
[35] R L Ledoux and J L White ldquoInfra red studies of hydrogenbonding interaction between kaolinite surfaces and intercalatedpotassium acetate hydrazine formamide and ureardquo Journal ofColloid and Interface Science vol 21 pp 27ndash52 1996
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
8 International Journal of Polymer Science
0 1 2 3 4 5 6
PPSCPSC
Salt concentration (wt)
Film codeP0PCPCS1PCS2PCS3PPCS1PPCS2PPCS3
minus1
minus7
minus8
minus9
minus10
minus11
minus12
726 times 10minus12
1017 times 10minus7
5 times 10minus10
294 times 10minus8
556 times 10minus11
220 times 10minus10
424 times 10minus9
331 times 10minus9
Bulk 120590 (Scm)
Log120590
(S cm
minus1)
Figure 10 Bulk ionic conductivity variation for PSC and PPSCwithweight of salt for composite system at room temperature (15∘C)
0
100
200
300
400
500
600
0
5
10
15
20
25
0 1 2 3 4 5 6Salt concentration (wt)
minus1
Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
clay)
syste
m
and
(PEO
+PM
MA+
clay)
PEO + clay
PEO + PMMA
PEO + PMMA + clay Elon
gatio
n at
bre
ak (m
m) f
or (P
EO+
PMM
A)
Figure 11 Variation of elongation at break for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
CPMMT which enhances the mobility of the PEO polymerThe highest elongation at break is obtained for the PCS2composite and beyond PCS2 elongation at break decreasesThe higher uniformity in the dispersion of salt and claywithin PEO is correlated with better adhesion between thecomponents of the composite due to the homogeneousdispersion of CPCMMT at PCS2 composition The decreasein the ductility beyond PCS2 is due to the restriction inchain mobility of the matrix and the filler particles acting asdefect points [29] This also shows that beyond certain limitof salt concentration the behavior changes Further at higher
20
40
60
80
100
120
140
160
0
200
400
600
800
1000
0 1 2 3 4 5 6Salt concentration (wt)
PEO + clay
PEO + PMMA
PEO + PMMA + clay
minus1
s mod
ulus
(Nm
m2) f
or (P
EO+
clay)
syste
mYo
ungrsquo
s mod
ulus
(Nm
m2)
and
(PEO
+PM
MA+
clay)
for (
PEO+
PMM
A)
Youn
grsquo
Figure 12 Variations of Youngrsquos modulus for PEOClay (PC)PEOPMMA and PEOPMMAClay (PPC) composite and blendcomposite system with varying content of salt
concentrations the polymers exist in agglomeration and theclay is not well dispersed The overall result is the increasein the ductility of the composite material with increasingsalt concentration The net increase in elongation at breakfor PCS system suggests filler induced dimensional stabilityto the composite electrolyte films making them capable ofsustaining and withstanding any external pressureshock to abetter level
36 Youngrsquos Modulus of PEOLiClO4CPMMT Composites
Youngrsquos modulus is a variable that describes the relationshipof stress to strain within the elastic region This is measuredfrom the slope of the curve within the elastic area of thespecimen The modulus of elasticity describes a materialrsquosstiffness the greater the modulus the stiffer the material Itquantifies the elasticity of the polymerIt is truly associatedwith primary and secondary chemical bonds Unlike the neatpolymer where the mechanical properties are determinedalmost entirely by matrix the mechanical properties of thecomposite depend on the interaction between the polymerand the added fillers From Figure 12 it is clear that Youngrsquosmodulus of the composites electrolyte decreases with theincreasing concentration of inorganic contents at constantclay levelThe influence of LiClO
4on the mechanical proper-
ties of PEOCPMMT film resembles the plasticization effectThe interaction between PEO and CPMMT is weakened bythe increasing content of salt The same behavior of Youngrsquosmodulus with filler has been reported earlier in the literature[29] As mechanical properties change by changing thecomposition of components as well as with the applied forcethey are difficult to analyze Also this decrease may probablybe explained in terms of debonding around polymer andclay interphases and void formation It can be concluded thatvalue of modulus depends highly on the distribution of fillerparticles in the polymer matrix which in turn depends on
International Journal of Polymer Science 9
the particleparticle interaction (agglomeration) andpolymerparticle interaction (adhesion and wetting) and morphologyof the filler particles [30]
37 Elongations at Break of PEOPMMALiClO4CPMMTBlend Composites System In order to have a more clear ideaof the change inmechanical properties of the blend compositesystem first the addition of salt to the blend system wasstudied for its effect on the mechanical properties and thenCPMMT was added to the same system and the sampleswere analyzed by UTM From the results given in Figure 11it is clear that elongation at break decreases initially withthe increasing concentration of salt to the blend system andthen starts increasing with higher salt concentration Thisdecrease in failure strain is due to the rigid filler additionwhich restricts the mobility of the PEO polymermolecules toflow freely past one another thus causing premature failureThe original elasticity of PEO is distorted due to the additionof PMMA and LiClO
4which is in close agreement with the
conclusion that the addition of rigid particles like PMMAinto the polymer matrix increases its stiffness and toughness[31 32] Compositeswith these properties can be used for heatresistant materials or product packaging materials
38 Youngrsquos Modulus of PEOPMMALiClO4CPMM Blend
Composites System Youngrsquos modulus of the PEOPMMA asa function of salt is shown in Figure 12 From this Figure itis clear that Youngrsquos modulus of the blend composite showsan overall decrease with the addition of salt This decreaseshows the weaker PEO interchain interaction and increasein the particle size of the inorganic phase because of localaggregations of particles in the presence of PMMA thesephenomenamay act as flaws in it [33 34]The same trend hasbeen confirmed by the SEM result as well This means thatthe addition of salt to the PEOPMMA composite suppressesthematerialrsquos stiffness and hence elasticity of the polymer Butwhen clay was added to the same PEOPMMASalt systeman enormous increase in the value of Young modulus wasobserved as shown in Figure 12 This is due to the interca-lation of polymer chains within the clay galleries that avoidsegmental motion of the polymer chains [35] Although thereis an overall decrease in the value of Young modulus of thePEOPMMALiClO
4CPMMT system with increasing salt
concentration still it is much higher than that of the virgin(neat) poly(ethylene oxide) (PEO) and PEOSaltCPMMTThis is in close agreement with the conclusion that theaddition of rigid particles like PMMA into the polymermatrix increases its stiffness [31]
4 Conclusions
This work used cetylpyridinium chloride to modify MMTmixed with higher molecular weight PEOLiClO
4and
PEOPMMALiClO4to produce composite materials The
experimental results showed that at constant salt contentthe addition of CPMMT first reduces crystallinity of PEOtill 33 wt of clay and then starts increasing at higher claycontent Thus 33 wt of clay was selected as the optimum
clay loadings for composites fabrication The XRD resultsshowed that the crystallinity of composites at optimum clayloading increases with increasing salt content and ionicconductivity obtained from impedance technique showeddeclining trend with higher salt content The addition of50wt of higher molecular weight PMMA to the com-posite of PEOSaltCPMMT affected the properties due tothe immiscibility or aggregation of filler within the poly-mer matrix however the blend composites showed bettermechanical performanceThe composite of PEOwith 35 wtof salt and 33 wt of CPMMT exhibited better performance
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] S Sultana Fabrication and studies on thin film composites ofPoly (Ethylene Oxide) [PhD thesis] University of PeshawarPeshawar Pakistan 2013
[2] T Lan P D Kaviratna and T J Pinnavaia ldquoEpoxy self-polymerization in smectite claysrdquo Journal of Physics and Chem-istry of Solids vol 57 no 6-8 pp 1005ndash1010 1996
[3] X Q Yang H S Lee L Hanson J McBreen and Y OkamotoldquoDevelopment of a new plasticizer for poly(ethylene oxide)-based polymer electrolyte and the investigation of their ion-pairdissociation effectrdquo Journal of Power Sources vol 54 no 2 pp198ndash204 1995
[4] R Mishra and K J Rao ldquoElectrical conductivity studies ofpoly(ethyleneoxide)-poly(vinylalcohol) blendsrdquo Solid State Ion-ics vol 106 no 1-2 pp 113ndash127 1998
[5] M S Khan A Shakoor and J Nisar ldquoConductance study ofpoly(ethylene oxide)- and poly(propylene oxide)-based poly-electrolytesrdquo Ionics vol 16 no 6 pp 539ndash542 2010
[6] Z Shen G P Simon and Y-B Cheng ldquoComparison ofsolution intercalation and melt intercalation of polymer-claynanocompositesrdquo Polymer vol 43 no 15 pp 4251ndash4260 2002
[7] P Aranda and E Ruiz-Hitzky ldquoNew polyelectrolyte materialsbased on smectite polyoxyethylene intercalation compoundsrdquoActa Polymerica vol 45 no 2 pp 59ndash67 1994
[8] D Ratna S Divekar A B Samui B C Chakraborty and AK Banthia ldquoPoly(ethylene oxide)clay nanocomposite thermo-mechanical properties andmorphologyrdquo Polymer vol 47 no 11pp 4068ndash4074 2006
[9] D Ratna S Divekar S Patchaiappan A B Samui and BC Chakraborty ldquoPoly(ethylene oxide)clay nanocomposites forsolid polymer electrolyte applicationsrdquo Polymer Internationalvol 56 no 7 pp 900ndash904 2007
[10] S K Lim JW Kim I Chin Y K Kwon andH J Choi ldquoPrepa-ration and interaction characteristics of organically modifiedmontmorillonite nanocomposite with miscible polymer blendof poly(ethylene oxide) and poly(methyl methacrylate)rdquo Chem-istry of Materials vol 14 no 5 pp 1989ndash1994 2002
[11] Y H Hyun S T Lim H J Choi and M S Jhon ldquoRheologyof poly(ethylene oxide)organoclay nanocompositesrdquo Macro-molecules vol 34 no 23 pp 8084ndash8093 2001
10 International Journal of Polymer Science
[12] H-W Chen C-Y Chiu and F-C Chang ldquoConductivity en-hancement mechanism of the poly(ethylene oxide)modified-clayLiClO
4systemsrdquo Journal of Polymer Science Part B Poly-
mer Physics vol 40 no 13 pp 1342ndash1353 2002[13] S Sultana M S Khan and M Humayun ldquoPreparation mor-
phology and thermal and optical properties of thin films offerric chloridepolyethylene oxide compositesrdquo Turkish Journalof Chemistry vol 36 no 5 pp 709ndash716 2012
[14] R Baskaran S Selvasekarapandian N Kuwata J Kawamuraand T Hattori ldquoConductivity and thermal studies of blendpolymer electrolytes based on PVAc-PMMArdquo Solid State Ionicsvol 177 no 26-32 pp 2679ndash2682 2006
[15] S K Lim S T Lim H B Kim I Chin and H J Choi ldquoPrepa-ration and physical characterization of polyepichlorohydrinelastomerclay nanocompositesrdquo Journal of MacromolecularScience Part B Physics vol 42 no 6 pp 1197ndash1208 2003
[16] B Chen and J R G Evans ldquoPreferential intercalation inpolymer-clay nanocompositesrdquo Journal of Physical Chemistry Bvol 108 no 39 pp 14986ndash14990 2004
[17] B Kumar and L G Scanlon ldquoPolymer-ceramic compositeelectrolytes conductivity and thermal history effectsrdquo SolidState Ionics vol 124 no 3 pp 239ndash254 1999
[18] J-H Chang S J Kim Y L Joo and S Im ldquoPoly(ethyleneterephthalate) nanocomposites by in situ interlayer polymeriza-tion the thermo-mechanical properties and morphology of thehybrid fibersrdquo Polymer vol 45 no 3 pp 919ndash926 2004
[19] X Qian N Gu Z Cheng X Yang E Wang and S DongldquoImpedance study of (PEO)
10LiClO
4-Al2O3composite polymer
electrolyte with blocking electrodesrdquo Electrochimica Acta vol46 no 12 pp 1829ndash1836 2001
[20] G J Brug A L G Van den Eeden M Sluyters-Rehbach and JH Sluyters ldquoThe analysis of electrode impedances complicatedby the presence of a constant phase elementrdquo Journal ofElectroanalytical Chemistry and Interfacial Electrochemistry vol176 no 1-2 pp 275ndash295 1984
[21] F Bellucci M Valentino T Monetta et al ldquoImpedance spec-troscopy of reactive polymers 1rdquo Journal of Polymer SciencePart B Polymer Physics vol 32 no 15 pp 2519ndash2527 1994
[22] J T S Irvine D C Sinclair and A R West ldquoElectroceramicscharacterization by impedance spectroscopyrdquo Advanced Mate-rials vol 2 no 3 pp 132ndash138 1990
[23] K V Kumar and G S Sundari ldquoConductivity studies of(PEO +KHCO
3) solid electrolyte system and its application
as an electrochemical cellrdquo Journal of Engineering Science andTechnology vol 5 no 2 pp 130ndash139 2010
[24] P C Srivastava in Solid State Ionics Materials and ApplicationsB V R Chowdar Ed pp 561ndash565 World Scientific Singapore1992
[25] S Ibrahim and M R Johan ldquoConductivity thermal andneural networkmodel nanocomposite solid polymer electrolytesystem (PEO-LiPF6-EC-CNT)rdquo International Journal of Elec-trochemical Science vol 6 no 11 pp 5565ndash5587 2011
[26] P P Chu M J Reddy and J Tsai ldquoStructural and transportcharacteristics of polyethylene oxidephenolic resin blend solidpolymer electrolytesrdquo Journal of Polymer Science Part B Poly-mer Physics vol 42 no 21 pp 3866ndash3875 2004
[27] H-W Chen C-Y Chiu and F-C Chang ldquoConductivityenhancement mechanism of the poly(ethylene oxide)modi-fied-clayLiClO
4systemsrdquo Journal of Polymer Science Part B
Polymer Physics vol 40 no 13 pp 1342ndash1353 2002
[28] K Jeddi N T Qazvini S H Jafari and H A KhonakdarldquoEnhanced ionic conductivity in PEOPMMA glassy misci-ble blends role of nano-confinement of minority componentchainsrdquo Journal of Polymer Science Part B Polymer Physics vol48 no 19 pp 2065ndash2071 2010
[29] S Ramesh and N B Khoo ldquoConductivity mechanical andthermal studies on poly(methyl methacrylate)-based polymerelectrolytes complexed with lithium tetraborate and propylenecarbonaterdquo Journal of Materials Engineering and Performancevol 21 no 1 pp 89ndash94 2012
[30] F Ali Synthesis and characterization of polyimidesilicabased nano-composites material [MPhil Thesis] University ofPeshawar Peshawar Pakistan 2006
[31] S Bai J Chen Z Huang and Z Yu ldquoThe role of the interfacialstrength in glass bead filled HDPErdquo Journal of Materials ScienceLetters vol 19 no 17 pp 1587ndash1589 2000
[32] G Nasar Synthesis and characterization of poly (vinyl alcohol)composites [MPhil thesis] University of Peshawar PeshawarPakistan 2008
[33] A Bandyopadhyay M de Sarkar and A K BhowmickldquoPoly(vinyl alcohol)silica hybrid nanocomposites by sol-geltechnique synthesis and propertiesrdquo Journal of Materials Sci-ence vol 40 no 19 pp 5233ndash5241 2005
[34] H B Kim J S Choi C H Lee S T Lim M S Jhon andH J Choi ldquoPolymer blendorganoclay nanocomposite withpoly(ethylene oxide) and poly(methylmethacrylate)rdquo EuropeanPolymer Journal vol 41 no 4 pp 679ndash685 2005
[35] R L Ledoux and J L White ldquoInfra red studies of hydrogenbonding interaction between kaolinite surfaces and intercalatedpotassium acetate hydrazine formamide and ureardquo Journal ofColloid and Interface Science vol 21 pp 27ndash52 1996
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
International Journal of Polymer Science 9
the particleparticle interaction (agglomeration) andpolymerparticle interaction (adhesion and wetting) and morphologyof the filler particles [30]
37 Elongations at Break of PEOPMMALiClO4CPMMTBlend Composites System In order to have a more clear ideaof the change inmechanical properties of the blend compositesystem first the addition of salt to the blend system wasstudied for its effect on the mechanical properties and thenCPMMT was added to the same system and the sampleswere analyzed by UTM From the results given in Figure 11it is clear that elongation at break decreases initially withthe increasing concentration of salt to the blend system andthen starts increasing with higher salt concentration Thisdecrease in failure strain is due to the rigid filler additionwhich restricts the mobility of the PEO polymermolecules toflow freely past one another thus causing premature failureThe original elasticity of PEO is distorted due to the additionof PMMA and LiClO
4which is in close agreement with the
conclusion that the addition of rigid particles like PMMAinto the polymer matrix increases its stiffness and toughness[31 32] Compositeswith these properties can be used for heatresistant materials or product packaging materials
38 Youngrsquos Modulus of PEOPMMALiClO4CPMM Blend
Composites System Youngrsquos modulus of the PEOPMMA asa function of salt is shown in Figure 12 From this Figure itis clear that Youngrsquos modulus of the blend composite showsan overall decrease with the addition of salt This decreaseshows the weaker PEO interchain interaction and increasein the particle size of the inorganic phase because of localaggregations of particles in the presence of PMMA thesephenomenamay act as flaws in it [33 34]The same trend hasbeen confirmed by the SEM result as well This means thatthe addition of salt to the PEOPMMA composite suppressesthematerialrsquos stiffness and hence elasticity of the polymer Butwhen clay was added to the same PEOPMMASalt systeman enormous increase in the value of Young modulus wasobserved as shown in Figure 12 This is due to the interca-lation of polymer chains within the clay galleries that avoidsegmental motion of the polymer chains [35] Although thereis an overall decrease in the value of Young modulus of thePEOPMMALiClO
4CPMMT system with increasing salt
concentration still it is much higher than that of the virgin(neat) poly(ethylene oxide) (PEO) and PEOSaltCPMMTThis is in close agreement with the conclusion that theaddition of rigid particles like PMMA into the polymermatrix increases its stiffness [31]
4 Conclusions
This work used cetylpyridinium chloride to modify MMTmixed with higher molecular weight PEOLiClO
4and
PEOPMMALiClO4to produce composite materials The
experimental results showed that at constant salt contentthe addition of CPMMT first reduces crystallinity of PEOtill 33 wt of clay and then starts increasing at higher claycontent Thus 33 wt of clay was selected as the optimum
clay loadings for composites fabrication The XRD resultsshowed that the crystallinity of composites at optimum clayloading increases with increasing salt content and ionicconductivity obtained from impedance technique showeddeclining trend with higher salt content The addition of50wt of higher molecular weight PMMA to the com-posite of PEOSaltCPMMT affected the properties due tothe immiscibility or aggregation of filler within the poly-mer matrix however the blend composites showed bettermechanical performanceThe composite of PEOwith 35 wtof salt and 33 wt of CPMMT exhibited better performance
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] S Sultana Fabrication and studies on thin film composites ofPoly (Ethylene Oxide) [PhD thesis] University of PeshawarPeshawar Pakistan 2013
[2] T Lan P D Kaviratna and T J Pinnavaia ldquoEpoxy self-polymerization in smectite claysrdquo Journal of Physics and Chem-istry of Solids vol 57 no 6-8 pp 1005ndash1010 1996
[3] X Q Yang H S Lee L Hanson J McBreen and Y OkamotoldquoDevelopment of a new plasticizer for poly(ethylene oxide)-based polymer electrolyte and the investigation of their ion-pairdissociation effectrdquo Journal of Power Sources vol 54 no 2 pp198ndash204 1995
[4] R Mishra and K J Rao ldquoElectrical conductivity studies ofpoly(ethyleneoxide)-poly(vinylalcohol) blendsrdquo Solid State Ion-ics vol 106 no 1-2 pp 113ndash127 1998
[5] M S Khan A Shakoor and J Nisar ldquoConductance study ofpoly(ethylene oxide)- and poly(propylene oxide)-based poly-electrolytesrdquo Ionics vol 16 no 6 pp 539ndash542 2010
[6] Z Shen G P Simon and Y-B Cheng ldquoComparison ofsolution intercalation and melt intercalation of polymer-claynanocompositesrdquo Polymer vol 43 no 15 pp 4251ndash4260 2002
[7] P Aranda and E Ruiz-Hitzky ldquoNew polyelectrolyte materialsbased on smectite polyoxyethylene intercalation compoundsrdquoActa Polymerica vol 45 no 2 pp 59ndash67 1994
[8] D Ratna S Divekar A B Samui B C Chakraborty and AK Banthia ldquoPoly(ethylene oxide)clay nanocomposite thermo-mechanical properties andmorphologyrdquo Polymer vol 47 no 11pp 4068ndash4074 2006
[9] D Ratna S Divekar S Patchaiappan A B Samui and BC Chakraborty ldquoPoly(ethylene oxide)clay nanocomposites forsolid polymer electrolyte applicationsrdquo Polymer Internationalvol 56 no 7 pp 900ndash904 2007
[10] S K Lim JW Kim I Chin Y K Kwon andH J Choi ldquoPrepa-ration and interaction characteristics of organically modifiedmontmorillonite nanocomposite with miscible polymer blendof poly(ethylene oxide) and poly(methyl methacrylate)rdquo Chem-istry of Materials vol 14 no 5 pp 1989ndash1994 2002
[11] Y H Hyun S T Lim H J Choi and M S Jhon ldquoRheologyof poly(ethylene oxide)organoclay nanocompositesrdquo Macro-molecules vol 34 no 23 pp 8084ndash8093 2001
10 International Journal of Polymer Science
[12] H-W Chen C-Y Chiu and F-C Chang ldquoConductivity en-hancement mechanism of the poly(ethylene oxide)modified-clayLiClO
4systemsrdquo Journal of Polymer Science Part B Poly-
mer Physics vol 40 no 13 pp 1342ndash1353 2002[13] S Sultana M S Khan and M Humayun ldquoPreparation mor-
phology and thermal and optical properties of thin films offerric chloridepolyethylene oxide compositesrdquo Turkish Journalof Chemistry vol 36 no 5 pp 709ndash716 2012
[14] R Baskaran S Selvasekarapandian N Kuwata J Kawamuraand T Hattori ldquoConductivity and thermal studies of blendpolymer electrolytes based on PVAc-PMMArdquo Solid State Ionicsvol 177 no 26-32 pp 2679ndash2682 2006
[15] S K Lim S T Lim H B Kim I Chin and H J Choi ldquoPrepa-ration and physical characterization of polyepichlorohydrinelastomerclay nanocompositesrdquo Journal of MacromolecularScience Part B Physics vol 42 no 6 pp 1197ndash1208 2003
[16] B Chen and J R G Evans ldquoPreferential intercalation inpolymer-clay nanocompositesrdquo Journal of Physical Chemistry Bvol 108 no 39 pp 14986ndash14990 2004
[17] B Kumar and L G Scanlon ldquoPolymer-ceramic compositeelectrolytes conductivity and thermal history effectsrdquo SolidState Ionics vol 124 no 3 pp 239ndash254 1999
[18] J-H Chang S J Kim Y L Joo and S Im ldquoPoly(ethyleneterephthalate) nanocomposites by in situ interlayer polymeriza-tion the thermo-mechanical properties and morphology of thehybrid fibersrdquo Polymer vol 45 no 3 pp 919ndash926 2004
[19] X Qian N Gu Z Cheng X Yang E Wang and S DongldquoImpedance study of (PEO)
10LiClO
4-Al2O3composite polymer
electrolyte with blocking electrodesrdquo Electrochimica Acta vol46 no 12 pp 1829ndash1836 2001
[20] G J Brug A L G Van den Eeden M Sluyters-Rehbach and JH Sluyters ldquoThe analysis of electrode impedances complicatedby the presence of a constant phase elementrdquo Journal ofElectroanalytical Chemistry and Interfacial Electrochemistry vol176 no 1-2 pp 275ndash295 1984
[21] F Bellucci M Valentino T Monetta et al ldquoImpedance spec-troscopy of reactive polymers 1rdquo Journal of Polymer SciencePart B Polymer Physics vol 32 no 15 pp 2519ndash2527 1994
[22] J T S Irvine D C Sinclair and A R West ldquoElectroceramicscharacterization by impedance spectroscopyrdquo Advanced Mate-rials vol 2 no 3 pp 132ndash138 1990
[23] K V Kumar and G S Sundari ldquoConductivity studies of(PEO +KHCO
3) solid electrolyte system and its application
as an electrochemical cellrdquo Journal of Engineering Science andTechnology vol 5 no 2 pp 130ndash139 2010
[24] P C Srivastava in Solid State Ionics Materials and ApplicationsB V R Chowdar Ed pp 561ndash565 World Scientific Singapore1992
[25] S Ibrahim and M R Johan ldquoConductivity thermal andneural networkmodel nanocomposite solid polymer electrolytesystem (PEO-LiPF6-EC-CNT)rdquo International Journal of Elec-trochemical Science vol 6 no 11 pp 5565ndash5587 2011
[26] P P Chu M J Reddy and J Tsai ldquoStructural and transportcharacteristics of polyethylene oxidephenolic resin blend solidpolymer electrolytesrdquo Journal of Polymer Science Part B Poly-mer Physics vol 42 no 21 pp 3866ndash3875 2004
[27] H-W Chen C-Y Chiu and F-C Chang ldquoConductivityenhancement mechanism of the poly(ethylene oxide)modi-fied-clayLiClO
4systemsrdquo Journal of Polymer Science Part B
Polymer Physics vol 40 no 13 pp 1342ndash1353 2002
[28] K Jeddi N T Qazvini S H Jafari and H A KhonakdarldquoEnhanced ionic conductivity in PEOPMMA glassy misci-ble blends role of nano-confinement of minority componentchainsrdquo Journal of Polymer Science Part B Polymer Physics vol48 no 19 pp 2065ndash2071 2010
[29] S Ramesh and N B Khoo ldquoConductivity mechanical andthermal studies on poly(methyl methacrylate)-based polymerelectrolytes complexed with lithium tetraborate and propylenecarbonaterdquo Journal of Materials Engineering and Performancevol 21 no 1 pp 89ndash94 2012
[30] F Ali Synthesis and characterization of polyimidesilicabased nano-composites material [MPhil Thesis] University ofPeshawar Peshawar Pakistan 2006
[31] S Bai J Chen Z Huang and Z Yu ldquoThe role of the interfacialstrength in glass bead filled HDPErdquo Journal of Materials ScienceLetters vol 19 no 17 pp 1587ndash1589 2000
[32] G Nasar Synthesis and characterization of poly (vinyl alcohol)composites [MPhil thesis] University of Peshawar PeshawarPakistan 2008
[33] A Bandyopadhyay M de Sarkar and A K BhowmickldquoPoly(vinyl alcohol)silica hybrid nanocomposites by sol-geltechnique synthesis and propertiesrdquo Journal of Materials Sci-ence vol 40 no 19 pp 5233ndash5241 2005
[34] H B Kim J S Choi C H Lee S T Lim M S Jhon andH J Choi ldquoPolymer blendorganoclay nanocomposite withpoly(ethylene oxide) and poly(methylmethacrylate)rdquo EuropeanPolymer Journal vol 41 no 4 pp 679ndash685 2005
[35] R L Ledoux and J L White ldquoInfra red studies of hydrogenbonding interaction between kaolinite surfaces and intercalatedpotassium acetate hydrazine formamide and ureardquo Journal ofColloid and Interface Science vol 21 pp 27ndash52 1996
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
10 International Journal of Polymer Science
[12] H-W Chen C-Y Chiu and F-C Chang ldquoConductivity en-hancement mechanism of the poly(ethylene oxide)modified-clayLiClO
4systemsrdquo Journal of Polymer Science Part B Poly-
mer Physics vol 40 no 13 pp 1342ndash1353 2002[13] S Sultana M S Khan and M Humayun ldquoPreparation mor-
phology and thermal and optical properties of thin films offerric chloridepolyethylene oxide compositesrdquo Turkish Journalof Chemistry vol 36 no 5 pp 709ndash716 2012
[14] R Baskaran S Selvasekarapandian N Kuwata J Kawamuraand T Hattori ldquoConductivity and thermal studies of blendpolymer electrolytes based on PVAc-PMMArdquo Solid State Ionicsvol 177 no 26-32 pp 2679ndash2682 2006
[15] S K Lim S T Lim H B Kim I Chin and H J Choi ldquoPrepa-ration and physical characterization of polyepichlorohydrinelastomerclay nanocompositesrdquo Journal of MacromolecularScience Part B Physics vol 42 no 6 pp 1197ndash1208 2003
[16] B Chen and J R G Evans ldquoPreferential intercalation inpolymer-clay nanocompositesrdquo Journal of Physical Chemistry Bvol 108 no 39 pp 14986ndash14990 2004
[17] B Kumar and L G Scanlon ldquoPolymer-ceramic compositeelectrolytes conductivity and thermal history effectsrdquo SolidState Ionics vol 124 no 3 pp 239ndash254 1999
[18] J-H Chang S J Kim Y L Joo and S Im ldquoPoly(ethyleneterephthalate) nanocomposites by in situ interlayer polymeriza-tion the thermo-mechanical properties and morphology of thehybrid fibersrdquo Polymer vol 45 no 3 pp 919ndash926 2004
[19] X Qian N Gu Z Cheng X Yang E Wang and S DongldquoImpedance study of (PEO)
10LiClO
4-Al2O3composite polymer
electrolyte with blocking electrodesrdquo Electrochimica Acta vol46 no 12 pp 1829ndash1836 2001
[20] G J Brug A L G Van den Eeden M Sluyters-Rehbach and JH Sluyters ldquoThe analysis of electrode impedances complicatedby the presence of a constant phase elementrdquo Journal ofElectroanalytical Chemistry and Interfacial Electrochemistry vol176 no 1-2 pp 275ndash295 1984
[21] F Bellucci M Valentino T Monetta et al ldquoImpedance spec-troscopy of reactive polymers 1rdquo Journal of Polymer SciencePart B Polymer Physics vol 32 no 15 pp 2519ndash2527 1994
[22] J T S Irvine D C Sinclair and A R West ldquoElectroceramicscharacterization by impedance spectroscopyrdquo Advanced Mate-rials vol 2 no 3 pp 132ndash138 1990
[23] K V Kumar and G S Sundari ldquoConductivity studies of(PEO +KHCO
3) solid electrolyte system and its application
as an electrochemical cellrdquo Journal of Engineering Science andTechnology vol 5 no 2 pp 130ndash139 2010
[24] P C Srivastava in Solid State Ionics Materials and ApplicationsB V R Chowdar Ed pp 561ndash565 World Scientific Singapore1992
[25] S Ibrahim and M R Johan ldquoConductivity thermal andneural networkmodel nanocomposite solid polymer electrolytesystem (PEO-LiPF6-EC-CNT)rdquo International Journal of Elec-trochemical Science vol 6 no 11 pp 5565ndash5587 2011
[26] P P Chu M J Reddy and J Tsai ldquoStructural and transportcharacteristics of polyethylene oxidephenolic resin blend solidpolymer electrolytesrdquo Journal of Polymer Science Part B Poly-mer Physics vol 42 no 21 pp 3866ndash3875 2004
[27] H-W Chen C-Y Chiu and F-C Chang ldquoConductivityenhancement mechanism of the poly(ethylene oxide)modi-fied-clayLiClO
4systemsrdquo Journal of Polymer Science Part B
Polymer Physics vol 40 no 13 pp 1342ndash1353 2002
[28] K Jeddi N T Qazvini S H Jafari and H A KhonakdarldquoEnhanced ionic conductivity in PEOPMMA glassy misci-ble blends role of nano-confinement of minority componentchainsrdquo Journal of Polymer Science Part B Polymer Physics vol48 no 19 pp 2065ndash2071 2010
[29] S Ramesh and N B Khoo ldquoConductivity mechanical andthermal studies on poly(methyl methacrylate)-based polymerelectrolytes complexed with lithium tetraborate and propylenecarbonaterdquo Journal of Materials Engineering and Performancevol 21 no 1 pp 89ndash94 2012
[30] F Ali Synthesis and characterization of polyimidesilicabased nano-composites material [MPhil Thesis] University ofPeshawar Peshawar Pakistan 2006
[31] S Bai J Chen Z Huang and Z Yu ldquoThe role of the interfacialstrength in glass bead filled HDPErdquo Journal of Materials ScienceLetters vol 19 no 17 pp 1587ndash1589 2000
[32] G Nasar Synthesis and characterization of poly (vinyl alcohol)composites [MPhil thesis] University of Peshawar PeshawarPakistan 2008
[33] A Bandyopadhyay M de Sarkar and A K BhowmickldquoPoly(vinyl alcohol)silica hybrid nanocomposites by sol-geltechnique synthesis and propertiesrdquo Journal of Materials Sci-ence vol 40 no 19 pp 5233ndash5241 2005
[34] H B Kim J S Choi C H Lee S T Lim M S Jhon andH J Choi ldquoPolymer blendorganoclay nanocomposite withpoly(ethylene oxide) and poly(methylmethacrylate)rdquo EuropeanPolymer Journal vol 41 no 4 pp 679ndash685 2005
[35] R L Ledoux and J L White ldquoInfra red studies of hydrogenbonding interaction between kaolinite surfaces and intercalatedpotassium acetate hydrazine formamide and ureardquo Journal ofColloid and Interface Science vol 21 pp 27ndash52 1996
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials
Submit your manuscripts athttpwwwhindawicom
ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CorrosionInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Polymer ScienceInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CeramicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CompositesJournal of
NanoparticlesJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Biomaterials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
NanoscienceJournal of
TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of
NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
CrystallographyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CoatingsJournal of
Advances in
Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Smart Materials Research
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MetallurgyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
BioMed Research International
MaterialsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nano
materials
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofNanomaterials