lcm processing and characterization of cnt modified
TRANSCRIPT
Microsoft PowerPoint - PUM Final
Presentation.pptxLCM Processing and Characterization of CNT Modified
Fibre Reinforced Composites.
M.Ubaid Ullah Khalid
Post Graduation: M.Sc Polymer Technology from Hochschule Aalen and Universität Bayreuth Session 2011 to 2013
Professional Fibre Craft Industries Affiliation: From August 2010 to February 2011
May 2013 to present
Core Area of Interest: Thermosetting resins based Fibre Reinforced composites
/ 3 /
WHAT IS FIBRE CRAFT INDUSTRIES? Intro: Pioneer in the field of advanced and high
performance composites in Pakistan.
Customers: Oil and Gas sector Chemical processing industry Marine industry Electrical Distribution Companies Defence organizations Power Plants Security Forces
Our BrandsOur Brands
Processes • Contact Molding • Pultrusion (Pultron) • Pulwinding • SMC • Roll Wraping • Filament Winding (Mclean Anderson) • Vacuum Infusion • RTM (Plastech UK) • Extrusion (Leistritz) • Thermoforming
FRP/GRP Pipes
Cooling Towers
upto 90,000 volts
liters
Porta Cabins
requirements.
/ 6 /
LCM Processing and Characterization of CNT Modified Fibre Reinforced Composites.
•What are CNTs?
•Influence on the Mechanical Properties of Nanocomposites and Hybrid Composites.
•Mechanisms of failure in CNT modified composites.
•How to insert CNTs into Hybrid Composites.
•How to determine whether CNTs are equally distributed in the composite.
Introduction
/ 8 /
• Annual increase of 8.2% in the demand of
composites.
Aerospace
Automobile
Anisotropy in composite properties
Kim and Khan (2011), IJASS (12) , 115133 Rajoria and Jalili (2005), Composite Science and Technology (65), 20792093 Yadama et al. (2006), Composites Part A (37), issue 3, 385392
Limitations related to composite‘s properties
In plane properties > Out of plane properties
Fatigue Damping Interlaminar properties
under comrpression
State of the art
Improving matrix dominated properties
A P Mouritz (2004) , Journal of Materials design and Application , Part L Fan et al. Composite: Part A 39 (2011)
/ 10 /
Carbon nanotubes
Carbon Nanotubes
Iijima , Nature (1991) Vol.354 (6348), 5658 Demcyzk et al. (2002), MatSci&Eng A 334 (12): 173178 Toho Tenax Europe
• Graphene sheets rolled into concentric cylinders. • Synthesized by Iijima in 1991.
Features: • Outstanding specific surface area (~1300 m2/g). • Excellent electrical (105107 S/m) and thermal (>3000 W/mK) conductivities.
Properties of Carbon Nanotubes compared with other materials
Material Young's Modulus
SWCNT 1054E - 5000T ~126T ~16E
MWCNT 800 – 950E ~150E - Carbon fiber ~430 ~5.3 1.5 - 2 E-Glass Fiber ~73 ~2.2 ~3,5 Epoxy ~3.5 0.08 1 - 10
Single walled and Multi walled CNTs
E- experimental result,T- theoretical results
Introduction
Integrating CNTs into FRPs
Bekyarova et al. ((2007) Langmunir Vol. 23, 39704 Jin et al. (2012) I&EC, Vol. 51 (13), 49274933 Li et al. (2009), Composites Part A; Vol.40 (12), 20042012
Direct growth of CNTs on fiber surface and Electrophoresis
Manufacturing of 3D fibers
• Electrophoresis • Transfer printing
• Dispersion of carbon nanotubes in the interlayers.
Matrix modification
Cloth ply Tows of MWCNT Covered fibers
Ni2+ C2H2
/ 13 /
Bekyarova et al. ((2007) Langmunir Vol. 23, 39704 Jin et al. (2012) I&EC, Vol. 51 (13), 49274933 Li et al. (2009), Composites Part A; Vol.40 (12), 20042012
Manufacturing of 3D fibers
• Electrophoresis • Transfer printing
• Dispersion of carbon nanotubes in the interlayers.
Matrix modification
CNT dispersion as an interlayer
State of the art Integrating CNTs into FRPs
/ 14 /
Bekyarova et al. ((2007) Langmunir Vol. 23, 39704 Jin et al. (2012) I&EC, Vol. 51 (13), 49274933 Li et al. (2009), Composites Part A; Vol.40 (12), 20042012
Manufacturing of 3D fibers
• Electrophoresis • Transfer printing
• Dispersion of carbon nanotubes in the interlayers.
Matrix modification
Direct mixing of CNTs into the matrix or matrix modification
State of the art Integrating CNTs into FRPs
Liquid composite molding
Issue related to CNT/epoxy processing
Green et al. Composites: Part A 40 (2009) 14701475 Romhany et al. Material Science Forum Vol. 589 (2008) 169274
• Filtration of CNTs by the reinforcement fabric. • Results in local variation in CNT content.
CNT filtration visible on a glass fiber laminate produced using RTM.
Intra tow filtration
CNT/Polymer
Agglomerates
• Manufacturing of hybrid composites. • Processing method: Liquid composite molding
• Development of effective physical characterization methods. • Evaluation of filtration.
• Determination ofmechanical properties. • Role of carbon nanotubes on fracture mechanisms.
Approach
/ 17 /
Nano- / Hybrid composites Processing : •Dispersion •Homogeneity Characterization : • Physical
• Based on intrinsic properties of CNTs
• Mechanical • Nanocomposites • Hybrid composites
/ 18 /
• BAYTUBES® (Multi walled CNTs) with different surface functionalitiesCarbon nanotubes
• E-Glass fiber fabric 701 g/m2 (Non woven unidirectional)
• Layup [0°]2s, [0°]3s
Reinforcement
• Neat epoxy (top), CNT/epoxy (bottom)
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0
20
40
60
80
100
120
140
160
180
Bending Modulus
10 µm
• Significant improvement by just 0.1 wt.% CNT. • Slight reduction after 0.5 wt.% due to tube-tube contacts. • Clearly altered fracture surface.
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 0,0
0,2
0,4
0,6
0,8
1,0
1,2
Critical stress intensity factor Stiffness from Saxena and Hudak method
Concentration / wt.%
K Ic /
M Pa
Fracture toughness
ISO 13586, CT specimen Test speed : 10 mm/min, 1 N Preload
Remarks: • Slight improvement in
fracture toughness. • Material inhomogeneities
unaffected.
Agglomerates
Thostenson & Chou J.Phys.D: Appl. Phys. 36 (2003) 573582
Thostenson and Chou Modification for random orientation of CNTs
Nomenclature ENC Stiffness of nanocomposite ENT Stiffness of nanotube Em Stiffness of matrix t Thickness of graphite layer NT Nanotube content AR Aspect ratio l Length of nanotube d Diameter of nanotube
Halpin Tsai for parallel orientation of
glass fiber
orientation of CNTs
orientation of CNTs
glass fiber
Modification by Thostenson & Chou regarding the eff. geometry of CNTs
),,,,,,( NTNTmNC tdlAREEfE
Thostenson & Chou (2003), Journal of Physics, Vol. 36, Iss. 5
0 400 800 1200 1600 2000 2400 2800 3200 0
10
20
30
40
50
60
70
80
Drawback: The models do not consider: • Agglomeration • Tube-tube contacts • CNT straightness
Diameter plays a more important role than the aspect ratio and smaller
diameter tubes have higher reinforcement capability.
For CNT content of 0.5 wt.%.
0 100 200 300 400 500 600 0
5
10
15
20
25
30
35
40
Dynamic mechanical analysis
Torsion Rectangular, Temp = 150 oC to 170 oC , ↑ΔT = 3 K/min, Strain amplitude = 0.1 % Results averaged for three samples Rajoria et al. (2005) CompSciTech Vol. 65 (14): 20792093
-120 -90 -60 -30 0 30 60 90 120 150
G ' /
P a
Stick-slip Mechanism
Enhanced loss modulus due to stick slip mechanism. Energy lost due to interfacial friction.
Results (CNT/epoxy nanocomposites)
Dynamic mechanical analysis
Torsion Rectangular, Temp = 150 oC to 170 oC , ↑ΔT = 3 K/min, Strain amplitude = 0.1 % Difference calculated at 25 °C Results averaged for three samples
-120 -90 -60 -30 0 30 60 90 120 150
G ' /
2,0x107
4,0x107
6,0x107
8,0x107
1,0x108
1,2x108
1,4x108
G " /
Neat epoxy CNT/epoxy (0.5 wt.%) CNT/epoxy (1.0 wt.%)
CNT content G improvement G´´ Improvement 0.5 wt.% 6 % 6 % 1.0 wt.% 16 % 30 %
Values on a linear scale to highlight the differences.
Liquid composite molding
Issue related to CNT/epoxy processing
Green et al. Composites: Part A 40 (2009) 14701475 Romhany et al. Material Science Forum Vol. 589 (2008) 169274
• Filtration of CNTs by the reinforcement fabric. • Results in local variation in CNT content.
CNT filtration visible on a glass fiber laminate produced using RTM.
Intra tow filtration
CNT/Polymer
Agglomerates
Resin Injection Point
Resin Injection Point
• Length of carbon nanotubes was measured using the TEM micrographs.
• CNT/epoxy dissolved into THF.
Results (CNT/epoxy nanocomposites)
Length distribution analysis Total nanotubes count > 400
0 200 400 600 800 1000 1200 1400 1600 0,00 0,02 0,04 0,06 0,08 0,10 0,12 0,14 0,16
Before Injection
No rm
al iz
ed F
re qu
en cy
C om
m ul
at iv
e no
rm al
iz ed
fr eq
ue nc
y
0 200 400 600 800 1000 1200 1400 1600 0,00 0,02 0,04 0,06 0,08 0,10 0,12 0,14 0,16
Nanotube Length Class / nm
No evidence of filtration was observed.
Only the filtration based on CNT length
was evaluated.
TEM micrograph
Dresselhaus et al. Philosophical transaction (2004) Vol. 362 20652098
•D-Band is associated to non- graphitic rings.
•D is an overtone of D-band.
D-band G-band
D‘-band
Results (Raman spectroscopy)
Dresselhaus et al. Philosophical transaction (2004) Vol. 362 20652098
400 800 1200 1600 2000 2400 2800 3200 3600 4000
0
25
50
75
100
~2660 cm-1 (D'-band) (overtone D-band)
~3065 cm-1
Aromatic stretch
~1610 cm-1
Raman spectroscopy can detect concentration differences more precisely than other techniques e.g. TGA, FTIR, thermal and electrical conductivity.
400 800 1200 1600 2000 2400 2800 3200 3600 4000 0
20
40
60
80
100
120
140
160
180
D-Band from CNTs
Aromatic band
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 0,0
0,4
0,8
1,2
1,6
Equation y = 2.18 * x
Confocal Raman microscope (objective 10x) Linear polarized lazer (HeNe = 632.8 nm) 10 measurements averaged for one spectrum
Results (Hybrid composites)
CNT content in hybrid composites
Confocal Raman microscope (objective 10x) Linear polarized lazer (HeNe = 632.8 nm) 10 measurements averaged for one spectrum
Slight tendency of filtration along the resin flow path.
0 4 8 12 16 20 0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
Fl ow
p at
h 0
Dynamic mechanical analysis
Torsion Rectangular, Temp = 150 oC to 170 oC , ↑ΔT = 3 K/min, Strain amplitude = 0.1 % Results averaged for three samples Khan et al. (2011) CompSci&Tech, Vol. 71, 14861494
• CNT content of only 0.5 wt.% showing remarkable improvement in hybrid composites.
• Improvement in damping which is important for fatigue life of composites.
108
109
1010
Fiber reinforced composite
107
108
109
G " /
Fiber reinforced composite
0 5 10 15 20 25 30 35 40 45 50 55 0
200
400
600
800
1000
1200
1400
1600
1800
ISO 15024, Calculated using modified compliance calibration or MCC
Obervations: • Slight improvement in GIc. • Enhanced fiber bridging in hybrid
composites.
40 µm
0 5 10 15 20 25 30 35 40 45 50 55 0
200
400
600
800
1000
1200
1400
1600
1800
ISO 15024, Calculated using modified compliance calibration or MCC
Obervations: • Slight improvement in GIc. • Enhanced fiber bridging in hybrid
composites.
Glass fiber
Mode II, ILSS and Tensile 90o
DIN 65563 (mode II) , DIN EN ISO 5275 (Tensile 90o), DIN EN ISO 14130 (ILSS)
Fiber reinforced composites Hybrid composites 0
10
20
30
40
50
60
70
80
Observations: • No improvement in fiber/matrix interface. • Absence of hackles on fracture surface in hybrid
composites.
Summary
/ 36 /
Nanocomposites
• Fracture toughness • Flexural testing • Tensile testing • DMA
Hybrid composites • Evaluation of mechanical properties. • Understanding of the mechanisms.
• Tensile (0° and 90°) • mode I and II interlaminar
fracture toughness • ILSS • Compression testing • DMA
ILSS and mode II
mode I
Tensile testing
Good understanding of mechanical and fracture mechanical mechanisms in nano- and hybrid composites was developed.
Conclusions
/ 37 /
• Effective characterization methods based on Raman spectroscopy and length distribution analysis were developed.
• Mechanical and fracture mechanical mechanisms in nano and hybrid composites were aprehended.
• Micromechanics modeling was done to signify the role of different CNTs towards reinforcement and the potential of CNTs.
/ 38 /
/ 39 /
Literature overview of CNT/epoxy nanocomposites
Gojny et al. CompSciTech (2005) Vol. 65 23002313 Martone et al. CompSciTech (2011) Vol. 71 11171123
Critical issues: • Surface functionality • Dispersion • Aspect ratio • Agglomeration
Gojny et al. 2005 0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
What other‘s did !
Literature overview of CNT/epoxy nanocomposites
Gojny et al. CompSciTech (2005) Vol. 65 23002313 Martone et al. CompSciTech (2011) Vol. 71 11171123
Rule of mixture :
What other‘s did !
Inam et al. 2010
Wichmann et al. 2006
Godara et al. 2009
Seyhan et al. 2008
Romhany et al. 2009
Warrier et al. 2010
Karapappas et al. 2009
Tsantzalis et al. 2007
Sadeghian et al. 2006
Yokozeki et al. 2007
Davis et al. 2011
Veedu et al. 2006
Khan and Kim, 2011
0,5
1,0
1,5
2,0
2,5
3,0
1.0
0.5
0.50.3
Literature overview of CNT modified FRPs
XDCNT : a mixture of SWCNTs, DWCNTs and MWCNTs CNT content in wt.%
DWCNT MWCNT CNF
No direct correlation between the CNT content and property modification exists.
What happened earlier !
M.Ubaid Ullah Khalid
Post Graduation: M.Sc Polymer Technology from Hochschule Aalen and Universität Bayreuth Session 2011 to 2013
Professional Fibre Craft Industries Affiliation: From August 2010 to February 2011
May 2013 to present
Core Area of Interest: Thermosetting resins based Fibre Reinforced composites
/ 3 /
WHAT IS FIBRE CRAFT INDUSTRIES? Intro: Pioneer in the field of advanced and high
performance composites in Pakistan.
Customers: Oil and Gas sector Chemical processing industry Marine industry Electrical Distribution Companies Defence organizations Power Plants Security Forces
Our BrandsOur Brands
Processes • Contact Molding • Pultrusion (Pultron) • Pulwinding • SMC • Roll Wraping • Filament Winding (Mclean Anderson) • Vacuum Infusion • RTM (Plastech UK) • Extrusion (Leistritz) • Thermoforming
FRP/GRP Pipes
Cooling Towers
upto 90,000 volts
liters
Porta Cabins
requirements.
/ 6 /
LCM Processing and Characterization of CNT Modified Fibre Reinforced Composites.
•What are CNTs?
•Influence on the Mechanical Properties of Nanocomposites and Hybrid Composites.
•Mechanisms of failure in CNT modified composites.
•How to insert CNTs into Hybrid Composites.
•How to determine whether CNTs are equally distributed in the composite.
Introduction
/ 8 /
• Annual increase of 8.2% in the demand of
composites.
Aerospace
Automobile
Anisotropy in composite properties
Kim and Khan (2011), IJASS (12) , 115133 Rajoria and Jalili (2005), Composite Science and Technology (65), 20792093 Yadama et al. (2006), Composites Part A (37), issue 3, 385392
Limitations related to composite‘s properties
In plane properties > Out of plane properties
Fatigue Damping Interlaminar properties
under comrpression
State of the art
Improving matrix dominated properties
A P Mouritz (2004) , Journal of Materials design and Application , Part L Fan et al. Composite: Part A 39 (2011)
/ 10 /
Carbon nanotubes
Carbon Nanotubes
Iijima , Nature (1991) Vol.354 (6348), 5658 Demcyzk et al. (2002), MatSci&Eng A 334 (12): 173178 Toho Tenax Europe
• Graphene sheets rolled into concentric cylinders. • Synthesized by Iijima in 1991.
Features: • Outstanding specific surface area (~1300 m2/g). • Excellent electrical (105107 S/m) and thermal (>3000 W/mK) conductivities.
Properties of Carbon Nanotubes compared with other materials
Material Young's Modulus
SWCNT 1054E - 5000T ~126T ~16E
MWCNT 800 – 950E ~150E - Carbon fiber ~430 ~5.3 1.5 - 2 E-Glass Fiber ~73 ~2.2 ~3,5 Epoxy ~3.5 0.08 1 - 10
Single walled and Multi walled CNTs
E- experimental result,T- theoretical results
Introduction
Integrating CNTs into FRPs
Bekyarova et al. ((2007) Langmunir Vol. 23, 39704 Jin et al. (2012) I&EC, Vol. 51 (13), 49274933 Li et al. (2009), Composites Part A; Vol.40 (12), 20042012
Direct growth of CNTs on fiber surface and Electrophoresis
Manufacturing of 3D fibers
• Electrophoresis • Transfer printing
• Dispersion of carbon nanotubes in the interlayers.
Matrix modification
Cloth ply Tows of MWCNT Covered fibers
Ni2+ C2H2
/ 13 /
Bekyarova et al. ((2007) Langmunir Vol. 23, 39704 Jin et al. (2012) I&EC, Vol. 51 (13), 49274933 Li et al. (2009), Composites Part A; Vol.40 (12), 20042012
Manufacturing of 3D fibers
• Electrophoresis • Transfer printing
• Dispersion of carbon nanotubes in the interlayers.
Matrix modification
CNT dispersion as an interlayer
State of the art Integrating CNTs into FRPs
/ 14 /
Bekyarova et al. ((2007) Langmunir Vol. 23, 39704 Jin et al. (2012) I&EC, Vol. 51 (13), 49274933 Li et al. (2009), Composites Part A; Vol.40 (12), 20042012
Manufacturing of 3D fibers
• Electrophoresis • Transfer printing
• Dispersion of carbon nanotubes in the interlayers.
Matrix modification
Direct mixing of CNTs into the matrix or matrix modification
State of the art Integrating CNTs into FRPs
Liquid composite molding
Issue related to CNT/epoxy processing
Green et al. Composites: Part A 40 (2009) 14701475 Romhany et al. Material Science Forum Vol. 589 (2008) 169274
• Filtration of CNTs by the reinforcement fabric. • Results in local variation in CNT content.
CNT filtration visible on a glass fiber laminate produced using RTM.
Intra tow filtration
CNT/Polymer
Agglomerates
• Manufacturing of hybrid composites. • Processing method: Liquid composite molding
• Development of effective physical characterization methods. • Evaluation of filtration.
• Determination ofmechanical properties. • Role of carbon nanotubes on fracture mechanisms.
Approach
/ 17 /
Nano- / Hybrid composites Processing : •Dispersion •Homogeneity Characterization : • Physical
• Based on intrinsic properties of CNTs
• Mechanical • Nanocomposites • Hybrid composites
/ 18 /
• BAYTUBES® (Multi walled CNTs) with different surface functionalitiesCarbon nanotubes
• E-Glass fiber fabric 701 g/m2 (Non woven unidirectional)
• Layup [0°]2s, [0°]3s
Reinforcement
• Neat epoxy (top), CNT/epoxy (bottom)
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0
20
40
60
80
100
120
140
160
180
Bending Modulus
10 µm
• Significant improvement by just 0.1 wt.% CNT. • Slight reduction after 0.5 wt.% due to tube-tube contacts. • Clearly altered fracture surface.
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 0,0
0,2
0,4
0,6
0,8
1,0
1,2
Critical stress intensity factor Stiffness from Saxena and Hudak method
Concentration / wt.%
K Ic /
M Pa
Fracture toughness
ISO 13586, CT specimen Test speed : 10 mm/min, 1 N Preload
Remarks: • Slight improvement in
fracture toughness. • Material inhomogeneities
unaffected.
Agglomerates
Thostenson & Chou J.Phys.D: Appl. Phys. 36 (2003) 573582
Thostenson and Chou Modification for random orientation of CNTs
Nomenclature ENC Stiffness of nanocomposite ENT Stiffness of nanotube Em Stiffness of matrix t Thickness of graphite layer NT Nanotube content AR Aspect ratio l Length of nanotube d Diameter of nanotube
Halpin Tsai for parallel orientation of
glass fiber
orientation of CNTs
orientation of CNTs
glass fiber
Modification by Thostenson & Chou regarding the eff. geometry of CNTs
),,,,,,( NTNTmNC tdlAREEfE
Thostenson & Chou (2003), Journal of Physics, Vol. 36, Iss. 5
0 400 800 1200 1600 2000 2400 2800 3200 0
10
20
30
40
50
60
70
80
Drawback: The models do not consider: • Agglomeration • Tube-tube contacts • CNT straightness
Diameter plays a more important role than the aspect ratio and smaller
diameter tubes have higher reinforcement capability.
For CNT content of 0.5 wt.%.
0 100 200 300 400 500 600 0
5
10
15
20
25
30
35
40
Dynamic mechanical analysis
Torsion Rectangular, Temp = 150 oC to 170 oC , ↑ΔT = 3 K/min, Strain amplitude = 0.1 % Results averaged for three samples Rajoria et al. (2005) CompSciTech Vol. 65 (14): 20792093
-120 -90 -60 -30 0 30 60 90 120 150
G ' /
P a
Stick-slip Mechanism
Enhanced loss modulus due to stick slip mechanism. Energy lost due to interfacial friction.
Results (CNT/epoxy nanocomposites)
Dynamic mechanical analysis
Torsion Rectangular, Temp = 150 oC to 170 oC , ↑ΔT = 3 K/min, Strain amplitude = 0.1 % Difference calculated at 25 °C Results averaged for three samples
-120 -90 -60 -30 0 30 60 90 120 150
G ' /
2,0x107
4,0x107
6,0x107
8,0x107
1,0x108
1,2x108
1,4x108
G " /
Neat epoxy CNT/epoxy (0.5 wt.%) CNT/epoxy (1.0 wt.%)
CNT content G improvement G´´ Improvement 0.5 wt.% 6 % 6 % 1.0 wt.% 16 % 30 %
Values on a linear scale to highlight the differences.
Liquid composite molding
Issue related to CNT/epoxy processing
Green et al. Composites: Part A 40 (2009) 14701475 Romhany et al. Material Science Forum Vol. 589 (2008) 169274
• Filtration of CNTs by the reinforcement fabric. • Results in local variation in CNT content.
CNT filtration visible on a glass fiber laminate produced using RTM.
Intra tow filtration
CNT/Polymer
Agglomerates
Resin Injection Point
Resin Injection Point
• Length of carbon nanotubes was measured using the TEM micrographs.
• CNT/epoxy dissolved into THF.
Results (CNT/epoxy nanocomposites)
Length distribution analysis Total nanotubes count > 400
0 200 400 600 800 1000 1200 1400 1600 0,00 0,02 0,04 0,06 0,08 0,10 0,12 0,14 0,16
Before Injection
No rm
al iz
ed F
re qu
en cy
C om
m ul
at iv
e no
rm al
iz ed
fr eq
ue nc
y
0 200 400 600 800 1000 1200 1400 1600 0,00 0,02 0,04 0,06 0,08 0,10 0,12 0,14 0,16
Nanotube Length Class / nm
No evidence of filtration was observed.
Only the filtration based on CNT length
was evaluated.
TEM micrograph
Dresselhaus et al. Philosophical transaction (2004) Vol. 362 20652098
•D-Band is associated to non- graphitic rings.
•D is an overtone of D-band.
D-band G-band
D‘-band
Results (Raman spectroscopy)
Dresselhaus et al. Philosophical transaction (2004) Vol. 362 20652098
400 800 1200 1600 2000 2400 2800 3200 3600 4000
0
25
50
75
100
~2660 cm-1 (D'-band) (overtone D-band)
~3065 cm-1
Aromatic stretch
~1610 cm-1
Raman spectroscopy can detect concentration differences more precisely than other techniques e.g. TGA, FTIR, thermal and electrical conductivity.
400 800 1200 1600 2000 2400 2800 3200 3600 4000 0
20
40
60
80
100
120
140
160
180
D-Band from CNTs
Aromatic band
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 0,0
0,4
0,8
1,2
1,6
Equation y = 2.18 * x
Confocal Raman microscope (objective 10x) Linear polarized lazer (HeNe = 632.8 nm) 10 measurements averaged for one spectrum
Results (Hybrid composites)
CNT content in hybrid composites
Confocal Raman microscope (objective 10x) Linear polarized lazer (HeNe = 632.8 nm) 10 measurements averaged for one spectrum
Slight tendency of filtration along the resin flow path.
0 4 8 12 16 20 0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
Fl ow
p at
h 0
Dynamic mechanical analysis
Torsion Rectangular, Temp = 150 oC to 170 oC , ↑ΔT = 3 K/min, Strain amplitude = 0.1 % Results averaged for three samples Khan et al. (2011) CompSci&Tech, Vol. 71, 14861494
• CNT content of only 0.5 wt.% showing remarkable improvement in hybrid composites.
• Improvement in damping which is important for fatigue life of composites.
108
109
1010
Fiber reinforced composite
107
108
109
G " /
Fiber reinforced composite
0 5 10 15 20 25 30 35 40 45 50 55 0
200
400
600
800
1000
1200
1400
1600
1800
ISO 15024, Calculated using modified compliance calibration or MCC
Obervations: • Slight improvement in GIc. • Enhanced fiber bridging in hybrid
composites.
40 µm
0 5 10 15 20 25 30 35 40 45 50 55 0
200
400
600
800
1000
1200
1400
1600
1800
ISO 15024, Calculated using modified compliance calibration or MCC
Obervations: • Slight improvement in GIc. • Enhanced fiber bridging in hybrid
composites.
Glass fiber
Mode II, ILSS and Tensile 90o
DIN 65563 (mode II) , DIN EN ISO 5275 (Tensile 90o), DIN EN ISO 14130 (ILSS)
Fiber reinforced composites Hybrid composites 0
10
20
30
40
50
60
70
80
Observations: • No improvement in fiber/matrix interface. • Absence of hackles on fracture surface in hybrid
composites.
Summary
/ 36 /
Nanocomposites
• Fracture toughness • Flexural testing • Tensile testing • DMA
Hybrid composites • Evaluation of mechanical properties. • Understanding of the mechanisms.
• Tensile (0° and 90°) • mode I and II interlaminar
fracture toughness • ILSS • Compression testing • DMA
ILSS and mode II
mode I
Tensile testing
Good understanding of mechanical and fracture mechanical mechanisms in nano- and hybrid composites was developed.
Conclusions
/ 37 /
• Effective characterization methods based on Raman spectroscopy and length distribution analysis were developed.
• Mechanical and fracture mechanical mechanisms in nano and hybrid composites were aprehended.
• Micromechanics modeling was done to signify the role of different CNTs towards reinforcement and the potential of CNTs.
/ 38 /
/ 39 /
Literature overview of CNT/epoxy nanocomposites
Gojny et al. CompSciTech (2005) Vol. 65 23002313 Martone et al. CompSciTech (2011) Vol. 71 11171123
Critical issues: • Surface functionality • Dispersion • Aspect ratio • Agglomeration
Gojny et al. 2005 0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
What other‘s did !
Literature overview of CNT/epoxy nanocomposites
Gojny et al. CompSciTech (2005) Vol. 65 23002313 Martone et al. CompSciTech (2011) Vol. 71 11171123
Rule of mixture :
What other‘s did !
Inam et al. 2010
Wichmann et al. 2006
Godara et al. 2009
Seyhan et al. 2008
Romhany et al. 2009
Warrier et al. 2010
Karapappas et al. 2009
Tsantzalis et al. 2007
Sadeghian et al. 2006
Yokozeki et al. 2007
Davis et al. 2011
Veedu et al. 2006
Khan and Kim, 2011
0,5
1,0
1,5
2,0
2,5
3,0
1.0
0.5
0.50.3
Literature overview of CNT modified FRPs
XDCNT : a mixture of SWCNTs, DWCNTs and MWCNTs CNT content in wt.%
DWCNT MWCNT CNF
No direct correlation between the CNT content and property modification exists.
What happened earlier !