quantitativeanalysisofdampingenhancementandpiezoelectric...

Research ArticleQuantitative Analysis ofDamping Enhancement andPiezoelectricEffect Mechanism of CNTsPMNEP Composites

Shiyue Pan 1 Meijuan Li 2 Fei Chen 1 Zhixiong Huang3 Qiang Shen 1

and Lianmeng Zhang1

1State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070 China2School of Chemistry Chemical Engineering and Life Sciences Wuhan University of Technology Wuhan 430070 China3School of Materials Science and Engineering Wuhan University of Technology Wuhan 430070 China

Correspondence should be addressed to Qiang Shen sqqf263net

Received 2 March 2018 Revised 2 June 2018 Accepted 11 June 2018 Published 30 July 2018

Academic Editor Marino Lavorgna

Copyright copy 2018 Shiyue Pan et al +is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

New types of piezoelectric damping materials including carbon nanotubes (CNTs)lead magnesium niobate (PMN)epoxy (EP)resin are developed +e tan δ area (TA) analysis method is selected to evaluate the damping properties which obviously clarifiesthe effect of maximum loss factor (tan δ) and effective temperature range on damping properties Furthermore the dominantfactor of damping enhancement is quantitatively analyzed via the value of TA Compared with PMN the interfacial friction ofCNTs acts as the dominant factor for the content less than 06wt +e maximum damping percentage of CNTs reaches 2914CNTs form loop circuits gradually with the content of CNTs increasing and electrical energy generated via piezoelectric effect ofPMN is efficiently dissipated through the conductive network +us PMN becomes the dominant factor as the content of CNTsexceeds 08 wt and the damping percentage reaches 4743 at the content of CNTs of 10 wt

1 Introduction

In the past few decades the viscoelastic material with aninherent high loss factor is widely applied in automobilesaircraft and military equipment to suppress vibration andimpact noises [1] For example soft viscoelastic layers inviscoelastic sandwich structures are provided as the dampingcomponent in order to improve dynamic response [2] A newtype of damping enhancement with piezoelectric and con-ductive materials as fillers has been developed by Hagood andvon Flotow [3 4] Electrical energy generated by piezoelectriceffect of piezoelectric ceramics can be efficiently dissipated byexternal electronic circuits [5] Conductive fillers are in-troduced into piezoelectric-ceramicpolymer composites aspassive electrical network such as carbon nanotubes (CNTs)carbon black (CB) graphite and aluminum particles [6ndash13]CNTs are widely used due to the high electric current carryingcapacity (1011sim1012Acm2) [14] It is revealed that the CNTs

provide superior conductivity at very low concentrationswhich can transfer electrical energy into thermal energy ef-ficiently [14] Tian et al reported a type of CNTslead zirc-onate titanate (PZT)EP composites +ey found that thegenerated electrical energy was well dissipated and the lossfactors of composites were improved by the incorporation ofPZT and CNT at critical electrical percolation [7 8] Car-poncin et al studied the influence of piezoelectric on dampingproperties of CNTsPZTpolyamide composites and it wasfound that the polarization of piezoelectric ceramic particlesimproved the loss factor of 20 reaching to 0052 [9] PMN asanother piezoelectric material with perovskite structure alsopossess high piezoelectric coefficient and dielectric permit-tivity PMN piezoelectric materials were used in 0ndash3 piezo-electric composites for damping enhancement gradually[10ndash12] Li and Du focused on damping properties of nitrile-butadiene rubberphenolic resinPMNCB composite Me-chanical energy was converted efficiently via piezoelectric

HindawiAdvances in Materials Science and EngineeringVolume 2018 Article ID 1253635 7 pageshttpsdoiorg10115520181253635

effect at PMN volume content of 50 and the maximum lossfactor reached 0813 [10]

Shamir et al found that adding CB to the compositesreduced the peak damping intensity but enhanced dampingat higher temperature and the effective damping temper-ature range was widened [15] Chang et al investigated thedamping property of polyurethane composites with differentultraviolet absorbents and they found that the tan δ in-creased at the temperature range of higher than the glasstransition temperature though the tan δmax was graduallyreduced [16] +us in this study tan δ area (TA) and lossmodulus area (LA) values are selected as damping perfor-mance parameter of materials which obviously clarify theeffect of maximum loss factor and effective temperaturerange on damping properties [17ndash20] Furthermore TAanalysis method can be used for quantitative analysis ofdamping enhancement

In this study conductive phase (CNTs) and piezoelectricphase (PMN) are introduced into epoxy matrix to fabricatepiezoelectric damping composites Electrical energy gener-ated via piezoelectric effect of PMN is efficiently dissipatedthrough conductive network+us damping performance ofCNTsPMNEP composites is effectively improved +edamping enhancement effect of each component is specif-ically clarified and the damping percentage is quantitativelyanalyzed based on the TA analysis method

2 Experimental Procedure

21Materials +e lead magnesium niobate (PMN) ceramicpowder was supplied by Baoding Hengsheng AcousticsElectron Apparatus Company with the mean particle size of1ndash10 μm +e dimensions of CNTs (supplied by XFNANO)were 10ndash20 nm in diameter and the purity of CNTs wasgt95 Epoxy resin used in experiment was diglycidyl etherof bisphenol-A type with an epoxide equivalent weight of185ndash200 geq +e curing agent used in experiment waspolyethylene polyamine which was supplied by Aladdin+emolecular formula was C2nH5nNn Epoxy resin was trans-ferred into three-dimensional network structure by catalyticpolymerization and addition polymerization reaction be-tween molecular chains when polyethylene polyamine wasintroduced into epoxy which resulted in the curing ofcomposites

22 Preparation of CNTsPMNEP Composites CNTs werefunctionalized by 3 1 H2SO4 (98)HNO3 (70) acidtreatment to obtain carboxyl and hydroxyl groups Matricesof epoxy resin (EP) with different contents of acid-treatedCNTs were made +en PMN ceramic was preprocessed bysilane coupling agents KH-560 to improve interfacial contactperformance and then added to CNTEP solution +esolution was stirred at 60degC for 12 h with magnetic stirrerand then placed in vacuum drying oven for gas evaporationFinally solution with curing agent was cast into a mold andcured for 5 h at room temperature with a subsequent step at105degC for 2 h

+e fracture surface analysis was performed by fieldemission scanning electron microscope (FE-SEM HitachiS-4800) +e investigation of viscoelastic behavior wasperformed by dynamic mechanical thermal analysis (DMAPYRIS-7e) Resistivity was tested by impedance analyzer(HP4294A)

23 TAAnalysisMethod +eTA analysis method is selectedto evaluate the damping properties which obviously clarifiesthe effect of maximum loss factor and effective temperaturerange on damping properties Fradkin et al proposed thedefinition of damping functions [21]

LA 1113946TR

TG

EPrimedT asymp EprimeG minusEprimeR( 1113857R

Ea( 1113857avg

π2

T2g (1)

TA 1113946TR

TG

tan δ dT asymp ln EprimeG minus ln EprimeR( 1113857R

Ea( 1113857avg

π2

T2g (2)

where EPrime is the loss modulus tan δ is the loss factor Tg isthe glass transition temperature EprimeG and EprimeR are the storagemodulus in glassy and rubbery states TG and TR are theinitial and final temperature of glass transition (Ea)avg is theactivation energy of the relaxation process and R is the gasconstant

Materials show obvious damping performances for theloss factor reaching 03 around damping peak which meanscomposites reach effective loss factor +us in this researchwe choose effective damping temperature range (tan δ ge 03)as integral region TG and TR in formulas (1) and (2) arereplaced with the initial and final temperature of which tan δreaches 03 +en TA values are obtained through integralcalculation of loss factor curves over the temperature rangeToshio Ogawa proposed that loss factor had more practicalsignificance than loss modulus in noise control and dampinganalysis [17] Amorphous polymer semicrystalline polymerand single damping peak copolymer were used as researchobjects and the functional relation between TA values andgroup numbers was shown as follows

TA a0 + 1113944n

i1aiXi (3)

where Xi is the number of group i ai is the regressioncoefficient which means the contribution of TA values byeach group and a0 is a constant

+e group contribution analysis method is used tocalculate theoretical TA values and develop a relation be-tween the contribution of each functional group anddamping properties +us TA values can be used forquantitative analysis of damping enhancement +edamping percentage of each component is quantitativelyanalyzed based on following formulas

TAi TAc minusTAc0 (4)

Di TAi

TActimes 100 (5)

2 Advances in Materials Science and Engineering

where Di is the damping percentage of component i TAiand TAc are the TA value of component i and compositeand TAc0 is the TA value of composite at 0wt content ofcomponent i

3 Results and Discussion

As shown in Figure 1 CNTs dispersed well in the chemicallyfunctionalized CNTsEP composites at 02 wt CNT con-tent which improves interfacial frictional energy dissipationof CNTs As we can see from the magnied SEM image theinterparticle distance between carbon nanotubes is veryclose When CNT content is up to 10 wt no obviousagglomeration is observed in the matrix and the dispersionstate in the whole region still keeps well With the content ofCNTs increasing some matrix-rich (not containing CNTs)regions appear and some CNTs entangle with each other asshown in Figure 1(c) As we can see from the magnied SEMimage the agglomeration of CNTs weakens the interfacialcontact between CNT llers and epoxy matrix

Dynamic mechanical analysis (DMA) of CNTsEPcomposites are shown in Figure 2(a) In general dampingmaterials reach maximum loss factor (tan δmax) at glasstransition temperature (Tg) Tg of CNTsEP composites is incorrespondence with pure epoxy materials tan δmax at Tgincreases sharply and reaches optimal value at the CNTcontent of 02 wt due to the interfacial friction whenCNTs uniformly dispersed in epoxy matrix High content ofCNTs widens eective temperature range while tan δmaxdecreases due to agglomeration of llers and high viscosityof composites us TA values are selected as dampingperformance parameter which obviously claries the eectof maximum loss factor and wide temperature range ondamping properties Based on loss factor curves of CNTsEPcomposites TA values of composites with dierent contentsof CNTs are obtained as shown in Figure 2(b) e frictionalenergy dissipation between conductive phase and epoxymatrix rises as the content of CNTs increases e TA valueof CNTsEP composites increases correspondingly andreaches the maximum value at 06 wt content of CNTs forthe reason that CNTs widen eective temperature range at06 wt content of CNTs compared to 02 wt CNTsEP

composite As the CNT content increases graduallyCNTsEP composites show higher viscosity e eectivetemperature range keeps constant when the content ofCNTs exceeds 08 wt e entanglement of CNTs inepoxy matrix results in the decrease of TA value Howeverthe eective temperature range is widened signicantlywhen the content of conductive phase exceeds percolationthreshold e TA value of CNTsEP composites increasesat CNT content of 20 wt consequently Damping per-centage of CNTs and epoxy matrix can be calculated byformulas (4) and (5) e damping percentage of CNTsshows the same trend with TA values and reaches 3222 atthe CNT content of 06 wt For the reason that CNTs areuniformly dispersed in epoxy matrix without obviousagglomeration behavior the interfacial friction is eec-tively promoted for damping enhancement

As shown in Figure 3 PMN is uniformly dispersed inepoxy matrix without obvious agglomeration Compositesshow strong interfacial compatibility between PMN andepoxy ough the viscosity of PMNEP composites in-creases at 60wt content of PMN the dispersion state inthe whole region can still keep well e viscosity increasessignicantly when the content of PMN reaches 80wt Asa result cohesive force between PMN and epoxy becomesweaker which causes the agglomeration of PMN ceramicpowders and even some holes show up in composites

As shown in Figure 4(a) Tg of PMNEP composites isaected obviously by the addition of PMN ceramics Tg shiftstoward high temperature region for the content less than40wt Tg of PMNEP composite is lower than pure epoxymaterial and the eective temperature range is ecientlywidened Based on loss factor curves of PMNEP compos-ites TA values of composites with dierent contents of PMNare obtained as shown in Figure 4(b) Piezoelectric eect ofPMN ceramic is generated by external force Bound chargeexists on the crystal surface which cannot be transferred intoother forms of energy As a result the enhancement ofdamping properties is mainly achieved by the interfacialfriction of PMN ceramics TA values of PMNEP compositesincrease with the increase in the content of PMN and reach144 at 40wt content of PMN On the one hand theinterfacial friction between llers and polymer chains over

5μm

500nm

(a)

5μm

500nm

(b)

5μm

500nm

(c)

Figure 1 Fracture surface of CNTsEP composites at dierent contents of CNTs (a) 02 wt (b) 10 wt and (c) 20 wt

Advances in Materials Science and Engineering 3

the transition range is enhanced with the increase in thecontent of PMN On the other hand llers reduce the freevolume of elastic polymers which results in the decrease ofviscoelastic damping It means that the increase in frictionalenergy dissipation can be massively oset by the decrease inviscoelastic damping of matrix thus TA values of PMNEPcomposites decrease correspondingly Damping percentageof PMN and EP can be calculated by (4) and (5) edamping percentage of PMN shows the similar trend withTA values and reaches 3395 at PMN content of 40wtPMN llers are uniformly dispersed in the matrix andimprove damping properties through frictional energydissipation eciently while maintaining the inherent vis-coelastic damping of epoxy However damping propertiescannot be improved obviously with the content of PMNexceeding 60wt e increase in frictional energy dissi-pation is massively oset by the decrease in viscoelasticdamping of epoxy matrix so the damping percentage ofPMN is merely 428 at 60wt PMN content

Loss factor curves of CNTs60wt PMNEP compositesare shown in Figure 5(a) e increase in frictional energydissipation can be massively oset by the decrease in free

volume of matrix at 60wt content of PMN and theimpact of piezoelectric eect on damping properties can besignicantly indicated As shown in Figure 5(a) tan δmaxincreases sharply at 10 wt content of CNTs Combinedwith TA values of CNTsEP composites the damping per-centage of each component is shown in Figure 5(b) TAvalues of CNTs60wt PMNEP composites increasegradually with the increasing content of CNTs and reach2126 at 10 wt CNT content e eect of piezoelectricphase (PMN) and conductive phase (CNTs) on dampingproperties can be explained from two aspects On the onehand the interfacial friction between llers and epoxymatrix promotes energy dissipation eciently On the otherhand piezoelectric eect of PMN results in the enrichmentof positive and negative charge on crystal surface enelectrical energy converted from mechanical energy is dis-sipated through continuous conductive network (CNTs)When the content of CNTs is less than 06 wt CNT llersexist as independent units rather than conductive networkus bound charge on the crystal surface cannot betransferred into other forms of energy e interfacial eectof CNTs is the dominant factor of damping enhancement

30μm

(a)

30μm

(b)

30μm

(c)

Figure 3 Fracture surface of PMNEP composites at dierent contents of PMN (a) 20wt (b) 60wt and (c) 80wt

0 50 100 150 200

01

02

03

04

05

06

07

A 0 wtB 02 wtC 06 wt

D 08 wtE 10 wtF 20 wt

BC D

EF

A

CNTsEPta

n δ

Temperature (degC)

(a)

0 02 06 08 10 20CNTs content (wt)

020406080

100

Dam

ping

()

0

5

10

15

EPCNTs

TA o

f CN

TsE

P (K

)

(b)

Figure 2 Damping properties of CNTsEP composites as a function of CNT content (a) loss factor curves (b) TA values and dampingpercentage


through frictional energy dissipation e damping per-centage of CNTs reaches 2914 at CNTcontent of 06 wte conductive network generates gradually for the contentexceeding 08wt Electrical energy generated via piezo-electric eect of PMN is dissipated in the form of thermalenergy thus piezoelectric phase (PMN) becomes the dom-inant factor of damping enhancement Damping percentageof PMN increases obviously and reaches 4743 at 10wtCNTcontent When the content of CNTs reaches percolationthreshold (10wt) the conversion eciency of electricalenergy is the highest When the CNT content increases to20wt the high viscosity of composites results in the ag-glomeration behavior of llers which reduces functionalenergy dissipation Furthermore high content of CNTs formsshort circuit network which decreases energy conversioneciency As a result TA values of CNTs60wt PMNEPcomposites and the damping percentage of PMN decreasee damping percentage of PMN shows the similar trend

with TA values It is indicated that damping properties ofcomposites are signicantly improved by piezoelectric eectof PMN us the eective method for damping enhance-ment of piezoelectric damping materials is to realize ecientenergy conversion by improving piezoelectric eect

As shown in Figure 6 the Rv value decreases apparentlyfor the content of CNTs exceeding 08 wt which impliesthat CNT particles gradually contact with each other at08 wt CNT content e Rv value is lower than 107 whenthe CNT content reaches 20 wt e formation status ofCNTconductive network at dierent CNTcontents is shownin Figure 7 When the content of CNTs is small (Figure 7(a))less than 06 wt the electrical network cannot form usthe piezoelectric eect of PMN has no signicant eect ondamping enhancement With the increase in CNT contentcarbon nanotubes start to form small loops around PMNparticles (Figure 7(b)) ose loop circuits are taken asconversion units to convert electrical energy into thermal

0 50 100 150 200

01

02

03

04

05

06

07



AB

CD

EF

CNTs60 wt PMNEP

tan δ

Temperature (degC)

(a)

0 02 06 08 10 20CNTs content (wt)

020406080

100

Dam

ping

()

0510152025

EPCNTsPMN

Ta o

f CN

Ts6

0 wt

PM

NE

P (K

)

(b)

Figure 5 Damping properties of CNTsPMNEP composites as a function of CNT content (a) loss factor curves (b) TA values anddamping percentage

0 50 100 150 200

01

02

03

04

05

06

07



C

B ED

FA

PMNEPta

n δ

Temperature (degC)

(a)

0 10 20 40 60 80PMN content (wt)

020406080

100

Dam

ping

()

0

5

10

15

EPPMN

TA o

f PM

NE

P (K

)

(b)

Figure 4 Damping properties of PMNEP composites as a function of PMN content (a) loss factor curves (b) TA values and dampingpercentage


energy As shown in Figure 5(b) the damping percentage ofPMN increases sharply at CNT content of 08 wt whichimplies that the electrical energy generated by piezoelectriceect of PMN is dissipated eciently e maximum energyconversion rate is obtained when the content of CNTsreaches percolation threshold (10 wt) However CNTnetwork forms short circuit when the CNT content reaches20 wt (Figure 7(c)) and electrical energy generated viapiezoelectric eect of PMN cannot be dissipated ecientlyus the enhancement of damping properties by piezo-electric eect is weakened

4 Conclusions

e present paper has provided a comprehensive studyabout quantitative analysis of damping properties based onthe TA analysis method e addition of high content ofconductive phase would reduce the damping peak intensitybut enhance damping at higher temperatures and the ef-fective damping temperature range is widened It is dicultto evaluate the comprehensive damping properties of ma-terials by choosing tan δmax as the only performance indexus in this research the TA value is selected to evaluatedamping properties e TA analysis method obviouslyclaries the eect of maximum loss factor (tan δ) and ef-fective temperature range on damping properties Andsynergies of piezoelectric phase and conductive phase arefurther researched

(1) e damping percentage of CNTs in CNTsEPcomposites reaches 3222 at CNT content of06 wt e maximum loss factor reaches 056 andthe eective temperature range is widened

(2) e damping percentage of PMN ceramics inPMNEP composites reaches 3395 at 40wt PMNcontent e increase in frictional energy dissipationcan be massively oset by the decrease in viscoelasticdamping of matrix when the content of PMN exceeds60wt So damping properties of PMNEP com-posites cannot be improved obviously and thedamping percentage of PMN is merely 428

(3) e interfacial eect of CNTs acts as the dominantfactor of damping enhancement for the content lessthan 06 wt in CNTsPMNEP composites and themaximum damping percentage reaches 2914However PMN becomes the dominant factor ofdamping enhancement with the content of CNTsincreasing and the damping percentage reaches4743 for the content of CNTs reaching percolationthreshold Synergies of piezoelectric phase andconductive phase result in the damping enhance-ment of CNTsPMNEP composites

Data Availability

e data used to support the ndings of this study areavailable from the corresponding author upon request

Epoxy matrixPMNCNTsPMNCNTs

(a)

Epoxy matrixPMNCNTsPMNCNTsTT

(b)


(c)

Figure 7 Formation status of CNT conductive network at dierent CNT contents

0 05 1 15 2CNTs content (wt)

107

108

109

CNTs60 wt PMNEP

Resis

tivity

(Ωmiddotcm

)

Figure 6 Resistivity of composites as a function of CNT content


Conflicts of Interest

+e authors declare that they have no conflicts of interest

Acknowledgments

+is work was financially supported by the NationalNatural Science Foundation of China (nos 51472188 and51521001) Natural Research Funds of Hubei Province(no 2016CFB583) Fundamental Research Funds for theCentral Universities in China State Key Laboratory ofAdvanced Electromagnetic Engineering and Technology(Huazhong University of Science and Technology) NationalKey Research and Development Program of China (nos2017YFB0310400 and 2018YFB0905600) and Joint Fund(Grant No 6141A02022223)

References

[1] Y B Liao and H A Sodano ldquoPiezoelectric damping of re-sistively shunted beams and optimal parameters for maxi-mum dampingrdquo Journal of Vibration and Acoustics vol 132no 4 pp 1014ndash1020 2010

[2] T H Cheng M Ren Z Z Li and Y D Shen ldquoVibration anddamping analysis of composite fiber reinforced wind blade withviscoelastic damping controlrdquo Advances in Materials Scienceand Engineering vol 2015 Article ID 146949 6 pages 2015

[3] R L Forward ldquoElectronic damping of vibrations in opticalstructuresrdquo Applied Optics vol 18 no 5 pp 690ndash698 1979

[4] N W Hagood and A von Flotow ldquoDamping of structuralvibrations with piezoelectric materials and passive electricalnetworkrdquo Journal of Sound and Vibration vol 146 no 2pp 243ndash268 1991

[5] D Carponcin E Dantras G Michon et al ldquoNew hybridpolymer nanocomposites for passive vibration damping byincorporation of carbon nanotubes and lead zirconate titanateparticlesrdquo Journal of Non-Crystalline Solids vol 409pp 20ndash26 2015

[6] M B Bryning M F Islam J M Kikkawa and A G YodhldquoVery low conductivity threshold in bulk isotropic single-walled carbon nanotube-epoxy compositesrdquo Advanced Ma-terials vol 17 no 9 pp 1186ndash1191 2005

[7] S Tian F J Cui and X D Wang ldquoNew type of piezo-damping epoxy-matrix composites with multi-walled carbonnanotubes and lead zirconate titanaterdquo Materials Lettervol 62 no 23 pp 3859ndash3861 2008

[8] S Tian and X D Wang ldquoFabrication and performances ofepoxymulti-walled carbon nanotubespiezoelectric ceramiccomposites as rigid piezo-damping materialsrdquo Journal ofMaterials Science vol 43 no 14 pp 4979ndash4987 2008

[9] D Carponcin E Dantras J Dandurand et al ldquoElectrical andpiezoelectric behavior of polyamidePZTCNT multifunc-tional nanocompositesrdquo Advanced Engineering Materialsvol 16 no 8 pp 1018ndash1025 2014

[10] J Li and M Du ldquoStudy on the piezoelectric and dampingproperties of NBRPFPMNCB compositesrdquo Advanced Sci-ence Letters vol 4 no 3 pp 675ndash680 2011

[11] Y B Wang H Yan and Z X Huang ldquoMechanical dynamicmechanical and electrical properties of conductive carbonblackpiezoelectric ceramicchlorobutyl rubber compositesrdquoPolymer-Plastics Technology and Engineering vol 51 no 1pp 105ndash110 2012

[12] M X Shi Z X Huang and L M Zhang ldquo+e effects of dynamicload on the damping performance of piezoelectric ceramicconductive carbonepoxy resin compositesrdquo Polymer-PlasticsTechnology and Engineering vol 49 no 10 pp 979ndash982 2010

[13] H M Zhang and X D He ldquoPiezoelectric modal dampingperformance of 0-3 piezoelectric composite with conductingphase numerical analysis and experimentsrdquo Polymers andPolymer Composites vol 22 no 3 pp 261ndash268 2014

[14] P Avouris T Hertel R Martel T Schmidt H R Shea andR E Walkup ldquoCarbon nanotubes nanomechanics manip-ulation and electronic devicesrdquo Applied Surface Sciencevol 141 no 3-4 pp 201ndash209 1999

[15] D Shamir A Siegmann and M Narkis ldquoVibration dampingand electrical conductivity of styrene-butyl acrylate randomcopolymers filled with carbon blackrdquo Journal of AppliedPolymer Science vol 115 no 4 pp 1922ndash1928 2010

[16] J Chang B Tian L Li and Y F Zheng ldquoMicrostructure anddamping property of polyurethane composites hybridizedwith ultraviolet absorbentsrdquo Advances in Materials Scienceand Engineering vol 2018 Article ID 9624701 9 pages 2018

[17] T Ogawa and T Yamada ldquoA numerical prediction of peakarea in loss factor for polymerrdquo Journal of Applied PolymerScience vol 53 no 12 pp 1663ndash1668 1994

[18] J J Fay C J Murphy D A +omas and L H SperlingldquoEffect of morphology crosslink density and miscibility oninterpenetrating polymer network damping effectivenessrdquoPolymer Engineering and Science vol 31 no 24 pp 1731ndash1741 1991

[19] D J Hourston and F-U SchaFer ldquoPoly(ether urethane)poly(ethyl methacrylate) IPNs with high damping characteristicsthe influence of the crosslink density in both networksrdquoJournal of Applied Polymer Science vol 62 no 12pp 2025ndash2037 1996

[20] K A Moly and S S Bhagawan ldquoCorrelation between themorphology and dynamic mechanical properties of ethylenevinyl acetatelinear low-density polyethylene blends effects ofthe blend ratio and compatibilizationrdquo Journal of AppliedPolymer Science vol 100 no 6 pp 4526ndash4538 2006

[21] D G Franklin J N Foster and L H Sperling ldquoA quantitativedetermination of the damping behavior of acrylic-basedinterpenetrating polymer networksrdquo Rubber Chemistry andTechnology vol 59 no 2 pp 255ndash262 1986


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Submit your manuscripts atwwwhindawicom

effect at PMN volume content of 50 and the maximum lossfactor reached 0813 [10]

Shamir et al found that adding CB to the compositesreduced the peak damping intensity but enhanced dampingat higher temperature and the effective damping temper-ature range was widened [15] Chang et al investigated thedamping property of polyurethane composites with differentultraviolet absorbents and they found that the tan δ in-creased at the temperature range of higher than the glasstransition temperature though the tan δmax was graduallyreduced [16] +us in this study tan δ area (TA) and lossmodulus area (LA) values are selected as damping perfor-mance parameter of materials which obviously clarify theeffect of maximum loss factor and effective temperaturerange on damping properties [17ndash20] Furthermore TAanalysis method can be used for quantitative analysis ofdamping enhancement

In this study conductive phase (CNTs) and piezoelectricphase (PMN) are introduced into epoxy matrix to fabricatepiezoelectric damping composites Electrical energy gener-ated via piezoelectric effect of PMN is efficiently dissipatedthrough conductive network+us damping performance ofCNTsPMNEP composites is effectively improved +edamping enhancement effect of each component is specif-ically clarified and the damping percentage is quantitativelyanalyzed based on the TA analysis method

2 Experimental Procedure

21Materials +e lead magnesium niobate (PMN) ceramicpowder was supplied by Baoding Hengsheng AcousticsElectron Apparatus Company with the mean particle size of1ndash10 μm +e dimensions of CNTs (supplied by XFNANO)were 10ndash20 nm in diameter and the purity of CNTs wasgt95 Epoxy resin used in experiment was diglycidyl etherof bisphenol-A type with an epoxide equivalent weight of185ndash200 geq +e curing agent used in experiment waspolyethylene polyamine which was supplied by Aladdin+emolecular formula was C2nH5nNn Epoxy resin was trans-ferred into three-dimensional network structure by catalyticpolymerization and addition polymerization reaction be-tween molecular chains when polyethylene polyamine wasintroduced into epoxy which resulted in the curing ofcomposites

22 Preparation of CNTsPMNEP Composites CNTs werefunctionalized by 3 1 H2SO4 (98)HNO3 (70) acidtreatment to obtain carboxyl and hydroxyl groups Matricesof epoxy resin (EP) with different contents of acid-treatedCNTs were made +en PMN ceramic was preprocessed bysilane coupling agents KH-560 to improve interfacial contactperformance and then added to CNTEP solution +esolution was stirred at 60degC for 12 h with magnetic stirrerand then placed in vacuum drying oven for gas evaporationFinally solution with curing agent was cast into a mold andcured for 5 h at room temperature with a subsequent step at105degC for 2 h

+e fracture surface analysis was performed by fieldemission scanning electron microscope (FE-SEM HitachiS-4800) +e investigation of viscoelastic behavior wasperformed by dynamic mechanical thermal analysis (DMAPYRIS-7e) Resistivity was tested by impedance analyzer(HP4294A)

23 TAAnalysisMethod +eTA analysis method is selectedto evaluate the damping properties which obviously clarifiesthe effect of maximum loss factor and effective temperaturerange on damping properties Fradkin et al proposed thedefinition of damping functions [21]

LA 1113946TR

TG

EPrimedT asymp EprimeG minusEprimeR( 1113857R

Ea( 1113857avg

π2

T2g (1)

TA 1113946TR

TG

tan δ dT asymp ln EprimeG minus ln EprimeR( 1113857R

Ea( 1113857avg

π2

T2g (2)

where EPrime is the loss modulus tan δ is the loss factor Tg isthe glass transition temperature EprimeG and EprimeR are the storagemodulus in glassy and rubbery states TG and TR are theinitial and final temperature of glass transition (Ea)avg is theactivation energy of the relaxation process and R is the gasconstant

Materials show obvious damping performances for theloss factor reaching 03 around damping peak which meanscomposites reach effective loss factor +us in this researchwe choose effective damping temperature range (tan δ ge 03)as integral region TG and TR in formulas (1) and (2) arereplaced with the initial and final temperature of which tan δreaches 03 +en TA values are obtained through integralcalculation of loss factor curves over the temperature rangeToshio Ogawa proposed that loss factor had more practicalsignificance than loss modulus in noise control and dampinganalysis [17] Amorphous polymer semicrystalline polymerand single damping peak copolymer were used as researchobjects and the functional relation between TA values andgroup numbers was shown as follows

TA a0 + 1113944n

i1aiXi (3)

where Xi is the number of group i ai is the regressioncoefficient which means the contribution of TA values byeach group and a0 is a constant

+e group contribution analysis method is used tocalculate theoretical TA values and develop a relation be-tween the contribution of each functional group anddamping properties +us TA values can be used forquantitative analysis of damping enhancement +edamping percentage of each component is quantitativelyanalyzed based on following formulas

TAi TAc minusTAc0 (4)

Di TAi

TActimes 100 (5)









5μm

500nm

(a)

5μm

500nm

(b)

5μm

500nm

(c)






30μm

(a)

30μm

(b)

30μm

(c)


0 50 100 150 200

01

02

03

04

05

06

07



BC D

EF

A

CNTsEPta

n δ

Temperature (degC)

(a)

0 02 06 08 10 20CNTs content (wt)

020406080

100

Dam

ping

()

0

5

10

15

EPCNTs

TA o

f CN

TsE

P (K

)

(b)






0 50 100 150 200

01

02

03

04

05

06

07



AB

CD

EF

CNTs60 wt PMNEP

tan δ

Temperature (degC)

(a)

0 02 06 08 10 20CNTs content (wt)

020406080

100

Dam

ping

()

0510152025

EPCNTsPMN

Ta o

f CN

Ts6

0 wt

PM

NE

P (K

)

(b)


0 50 100 150 200

01

02

03

04

05

06

07



C

B ED

FA

PMNEPta

n δ

Temperature (degC)

(a)

0 10 20 40 60 80PMN content (wt)

020406080

100

Dam

ping

()

0

5

10

15

EPPMN

TA o

f PM

NE

P (K

)

(b)




4 Conclusions





Data Availability



(a)


(b)


(c)



107

108

109

CNTs60 wt PMNEP

Resis

tivity

(Ωmiddotcm

)





Acknowledgments


References

























Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls











5μm

500nm

(a)

5μm

500nm

(b)

5μm

500nm

(c)






30μm

(a)

30μm

(b)

30μm

(c)


0 50 100 150 200

01

02

03

04

05

06

07



BC D

EF

A

CNTsEPta

n δ

Temperature (degC)

(a)

0 02 06 08 10 20CNTs content (wt)

020406080

100

Dam

ping

()

0

5

10

15

EPCNTs

TA o

f CN

TsE

P (K

)

(b)






0 50 100 150 200

01

02

03

04

05

06

07



AB

CD

EF

CNTs60 wt PMNEP

tan δ

Temperature (degC)

(a)

0 02 06 08 10 20CNTs content (wt)

020406080

100

Dam

ping

()

0510152025

EPCNTsPMN

Ta o

f CN

Ts6

0 wt

PM

NE

P (K

)

(b)


0 50 100 150 200

01

02

03

04

05

06

07



C

B ED

FA

PMNEPta

n δ

Temperature (degC)

(a)

0 10 20 40 60 80PMN content (wt)

020406080

100

Dam

ping

()

0

5

10

15

EPPMN

TA o

f PM

NE

P (K

)

(b)




4 Conclusions





Data Availability



(a)


(b)


(c)



107

108

109

CNTs60 wt PMNEP

Resis

tivity

(Ωmiddotcm

)





Acknowledgments


References

























Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls







30μm

(a)

30μm

(b)

30μm

(c)


0 50 100 150 200

01

02

03

04

05

06

07



BC D

EF

A

CNTsEPta

n δ

Temperature (degC)

(a)

0 02 06 08 10 20CNTs content (wt)

020406080

100

Dam

ping

()

0

5

10

15

EPCNTs

TA o

f CN

TsE

P (K

)

(b)






0 50 100 150 200

01

02

03

04

05

06

07



AB

CD

EF

CNTs60 wt PMNEP

tan δ

Temperature (degC)

(a)

0 02 06 08 10 20CNTs content (wt)

020406080

100

Dam

ping

()

0510152025

EPCNTsPMN

Ta o

f CN

Ts6

0 wt

PM

NE

P (K

)

(b)


0 50 100 150 200

01

02

03

04

05

06

07



C

B ED

FA

PMNEPta

n δ

Temperature (degC)

(a)

0 10 20 40 60 80PMN content (wt)

020406080

100

Dam

ping

()

0

5

10

15

EPPMN

TA o

f PM

NE

P (K

)

(b)




4 Conclusions





Data Availability



(a)


(b)


(c)



107

108

109

CNTs60 wt PMNEP

Resis

tivity

(Ωmiddotcm

)





Acknowledgments


References

























Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls







0 50 100 150 200

01

02

03

04

05

06

07



AB

CD

EF

CNTs60 wt PMNEP

tan δ

Temperature (degC)

(a)

0 02 06 08 10 20CNTs content (wt)

020406080

100

Dam

ping

()

0510152025

EPCNTsPMN

Ta o

f CN

Ts6

0 wt

PM

NE

P (K

)

(b)


0 50 100 150 200

01

02

03

04

05

06

07



C

B ED

FA

PMNEPta

n δ

Temperature (degC)

(a)

0 10 20 40 60 80PMN content (wt)

020406080

100

Dam

ping

()

0

5

10

15

EPPMN

TA o

f PM

NE

P (K

)

(b)




4 Conclusions





Data Availability



(a)


(b)


(c)



107

108

109

CNTs60 wt PMNEP

Resis

tivity

(Ωmiddotcm

)





Acknowledgments


References

























Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls





4 Conclusions





Data Availability



(a)


(b)


(c)



107

108

109

CNTs60 wt PMNEP

Resis

tivity

(Ωmiddotcm

)





Acknowledgments


References

























Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls






Acknowledgments


References

























Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls






Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls




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