i
TENSILE, THERMAL AND ELECTRICAL CONDUCTIVITY PROPERTIES OF
EPOXY COMPOSITES CONTAINING CARBON BLACK AND GRAPHENE
NANOPLATELETS
By
Aaron S. Krieg
A THESIS
Submitted in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE
In Chemical Engineering
MICHIGAN TECHNOLOGICAL UNIVERSITY
2018
© 2018 Aaron S. Krieg
ii
This thesis has been approved in partial fulfillment of the requirements for the Degree of
MASTER OF SCIENCE in Chemical Engineering.
Department of Chemical Engineering
Thesis Advisor: Dr. Julia A. King
Committee Member: Dr. Gregory Odegard
Committee Member: Dr. Ibrahim Miskioglu
Department Chair: Dr. Pradeep Agrawal
i
Table of Contents
List of figures ..................................................................................................................... iv
List of tables ...................................................................................................................... vii
Preface..................................................................................................................................x
Acknowledgements ............................................................................................................ xi
Abstract ............................................................................................................................. xii
1 Introduction .................................................................................................................1
1.1 References ........................................................................................................2
2 Materials .....................................................................................................................5
2.1 Materials ...........................................................................................................5
2.2 Matrix Material .................................................................................................5
2.3 Filler Materials .................................................................................................8
2.3.1 Asbury Carbons TC307 Graphene Nanoplatelets ...............................8
2.3.2 Akzo Nobel EC-600 JD Carbon Black ...............................................9
2.4 Formulation Naming Convention ...................................................................10
2.5 References ......................................................................................................11
3 Fabrication and Experimental Methods ....................................................................12
3.1 Fabrication Methods .......................................................................................12
3.1.1 Neat Epoxy Test Specimen Fabrication ............................................15
3.1.2 TC307 GNP/Epoxy Test Specimen Fabrication ...............................16
3.1.3 Ketjenblack EC-600 JD CB/Epoxy Test Specimen Fabrication .......17
3.1.4 TC307 GNP/Ketjenblack EC-600 JD CB/Epoxy Test Specimen
Fabrication ........................................................................................18
3.2 Experimental Test Methods ............................................................................18
3.2.1 Field Emission Scanning Electron Microscopy (FESEM) Test
Method ..............................................................................................18
3.2.2 Through-Plane Electrical Resistivity Test Method ...........................26
3.2.3 In-Plane Electrical Resistivity Test Method .....................................27
3.2.4 Thermal Conductivity: Guarded Heat Flow Meter Test Method ......29
3.2.5 Mechanical Tensile Property Test Method .......................................31
3.3 References ......................................................................................................33
ii
4 Results .......................................................................................................................35
4.1 Microscopy Results ........................................................................................35
4.1.1 Asbury Carbon’s TC307 GNP in Epoxy Microscopy Results .........35
4.1.2 Akzo Nobel’s Ketjenblack EC-600 JD CB in Epoxy Microscopy
Results ..............................................................................................38
4.2 Electrical Resistivity Results ..........................................................................40
4.2.1 Asbury Carbon’s TC307 GNP in Epoxy Electrical Resistivity
Results ..............................................................................................40
4.2.2 Akzo Nobel’s Ketjenblack EC-600 JD CB in Epoxy Electrical
Resistivity Results ............................................................................42
4.2.3 TC307 GNP and Ketjenblack EC-600 JD CB in Epoxy Electrical
Resistivity Results ............................................................................44
4.2.4 Determining Synergistic Effects of Multiple Fillers on Electrical
Resistivity .........................................................................................46
4.3 Thermal Conductivity Results ........................................................................48
4.3.1 Asbury Carbon’s TC307 GNP in Epoxy Thermal Conductivity
Results ..............................................................................................48
4.3.2 Akzo Nobel’s EC-600 JD CB in Epoxy Thermal Conductivity
Results ..............................................................................................49
4.3.3 TC307 GNP and EC-600 JD CB in Epoxy Thermal Conductivity
Results ..............................................................................................50
4.4 Tensile Results ...............................................................................................51
4.4.1 Asbury Carbon’s TC307 GNP in Epoxy Tensile Results .................51
4.4.2 Akzo Nobel’s EC-600 JD CB in Epoxy Tensile Results ..................53
4.4.3 TC307 GNP and EC-600 JD CB in Epoxy Tensile Results .............56
4.4.4 Tensile Modulus Modeling ...............................................................59
4.5 References ......................................................................................................62
5 Conclusions and Future Work ..................................................................................65
5.1 Electrical Resistivity Properties for Neat Epoxy, GNP/Epoxy, CB/Epoxy,
and GNP/CB/Epoxy Composites ...................................................................66
5.2 Thermal Conductivity Properties for Neat Epoxy, GNP/Epoxy, CB/Epoxy,
and GNP/CB/Epoxy Composites ...................................................................68
5.3 Tensile Properties for Neat Epoxy, GNP/Epoxy, CB/Epoxy, and
GNP/CB/Epoxy Composites ..........................................................................68
5.4 Recommendations for Future Work ...............................................................70
iii
A Appendix A: Electrical Resistivity Results...............................................................72
B Appendix B: Thermal Conductivity Results at 55°C ................................................79
C Appendix C: Tensile Results ....................................................................................83
D Copyright documentation..........................................................................................93
iv
List of figures
Figure 2-1: Formation of EPON™ Resin 862 from Epichlorohydrin and Bisphenol F…..6
Figure 2-2: EPIKURE™ Curing Agent W Structure……………………………………..6
Figure 2-3: Crosslinking of EPON™ Resin 862 with EPIKURE™ Curing Agent W……7
Figure 2-4: Structure of Graphene Nanoplatelets…………………………………………8
Figure 2-5: Structure of Carbon Black Aggregate………………………………………...9
Figure 3-1: FlackTek SpeedMixer DAC 150.1 FVZ…………………………………….12
Figure 3-2: Steel Rectangular Bar Molds, Steel Disk-Molds……………………………13
Figure 3-3: Fisher Isotemp® Vacuum Oven Model 282A with a Welch 1402
DuoSeal®……………………………………………………………………15
Figure 3-4: Hitachi S-4700 Field Emission Scanning Electron Microscope (FESEM)…19
Figure 3-5: Delta Shopmaster 16” Variable Speed Scroll Saw with Quickset II Blade…20
Figure 3-6: Cressington 208HR High Resolution Sputter Coater with a Cressington…..20
Figure 3-7: Logitech Vacuum Impregnator……………………………………………...21
Figure 3-8: Struers LaboForce-3 Metallographic Specimen Grinder/Polisher…………..23
Figure 3-9: Buehler EcoMet 4 Rotary Polisher………………………………………….24
Figure 3-10: Buehler VibroMet I Vibratory Polisher……………………………………25
Figure 3-11: March Jupiter II Reactive Ion Etcher………………………………………26
Figure 3-12: Keithley 6517A Electrometer/High Resistance Meter……………………..27
Figure 3-13: Diagram of Through Plane Electrical Resistivity Test…………………….27
Figure 3-14: Keithley 2400 Source Meter……………………………………………….28
Figure 3-15: Netzsch Model TCA 300 Thermal Conductivity Analyzer………………..30
Figure 3-16: Circle Grinder……………………………………………………………...30
Figure 3-17: Diagram of Through-Plane Thermal Conductivity Test Method………….31
v
Figure 3-18: Ceast Router………………………………………………………………..32
Figure 3-19: Tinus Olsen Hydraulic Mechanical Testing Machine With Epsilon
Axial Extensometer………………………………………………….…...…33
Figure 4-1: Field Emission Microscope Micrograph of 5 wt% TC307 GNP in Epoxy at
x10,000 Magnification……………………………………………….………35
Figure 4-2: Field Emission Microscope Micrograph of 5 wt% TC307 GNP in Epoxy at
x30,000 Magnification……………………………………………….……....36
Figure 4-3: Field Emission Microscope Micrograph of 10 wt% TC307 GNP in
Epoxy at x10,000 Magnification.....................................................................37
Figure 4-4: Field Emission Microscope Micrograph of 10 wt% TC307 GNP in
Epoxy at x30,000 Magnification.....................................................................37
Figure 4-5: Field Emission Microscope Micrograph of 1 wt% EC-600 JD in Epoxy at
x50,000 Magnification…………………………………………………...…..38
Figure 4-6: Field Emission Microscope Micrograph of 1 wt% EC-600 JD in Epoxy at
x100,000 Magnification………...……………………………………….…..39
Figure 4-7: Field Emission Microscope Micrograph of 1 wt% EC-600 JD in Epoxy at
x200,000 Magnification……………………………………………………..39
Figure 4-8: Log (electrical resistivity) results for TC307 GNP/Epoxy Composites….....42
Figure 4-9: Log (Electrical Resistivity) Results for Ketjenblack EC-600 JD
CB/Epoxy…………………………………………………………………….44
Figure 4-10: Log (Electrical Resistivity) Results for Ketjenblack EC-600 JD/TC307
Epoxy Composites……………………………………………………...….46
Figure 4-11: Ultimate Tensile Strength Results for TC307 GNP in Epoxy
Composites…………………………………………………………………52
Figure 4-12: Strain at Ultimate Strength Results for TC307 GNP in Epoxy
Composites………………………………………………………………....53
Figure 4-13: Tensile Modulus Results for TC307 GNP in Epoxy Composites………….53
Figure 4-14: Ultimate Tensile Strength Results for Ketjenblack EC-600 JD CB in Epoxy
Composites…………………………………………………………………55
Figure 4-15: Strain at Ultimate Tensile Strength Results for Ketjenblack EC-600 JD CB
in Epoxy Composites……………………………………………………....55
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Figure 4-16: Tensile Modulus Results for Ketjenblack EC-600 JD CB in Epoxy………56
Figure 4-17: Ultimate Tensile Strength Results for Ketjenblack EC-600 JD CB and
TC307 GNP in Epoxy Composites……………………………….………..57
Figure 4-18: Strain at Ultimate Tensile Strength Results for Ketjenblack
EC-600 JD CB and TC307 GNP in Epoxy Composites………...………….58
Figure 4-19: Tensile Modulus Results for Ketjenblack EC-600 JD CB and TC307
GNP in Epoxy Composites………………….…………………………..…58
Figure 4-20: Tensile Modulus of GNP/Epoxy Composites with Einstein, Guth-
Smallwood, and 3D Halpin-Tsai Models ………………………………….62
Figure C-1: Tensile Results for Neat Epoxy……………...……………………………...83
Figure C-2: Tensile Results for 5 wt% TC307 GNP in Epoxy Composites…………......84
Figure C-3: Tensile Results for 10 wt% TC307 GNP in Epoxy Composites……………85
Figure C-4: Tensile Results for 15 wt% TC307 GNP in Epoxy Composites……………86
Figure C-5: Tensile Results for 20 wt% TC307 GNP in Epoxy Composites……………87
Figure C-6: Tensile Results for 0.33 wt% Ketjenblack EC-600 JD CB in Epoxy
Composites……………………………………...…………………………...88
Figure C-7: Tensile Results for 0.67 wt% Ketjenblack EC-600 JD in Epoxy
Composites…………………………………………………………………...89
Figure C-8: Tensile Results for 1 wt% Ketjenblack EC-600 JD in Epoxy
Composites………………………………………………………………....90
Figure C-9: Tensile Results for 0.33 wt% Ketjenblack EC-600 JD CB and 5 wt% TC307
GNP in Epoxy Composites………………………………………………….91
Figure C-10: Tensile Results for 0.33 wt% Ketjenblack EC-600 JD CB and 10 wt%
TC307 GNP in Epoxy Composites…………………………………………92
vii
List of tables
Table 3-1: Filler Loading Levels in Epoxy…………………………………...………….14
Table 3-2: Grinding and Polishing Steps……………………………………….………..22
Table 4-1: Electrical Resistivity Results for TC307 GNP in Epoxy Composites………..41
Table 4-2: Electrical Resistivity Results for Ketjenblack EC-600 JD CB in Epoxy…….43
Table 4-3: Electrical Resistivity Results for Ketjenblack EC-600 JD CB/TC307
GNP………………………………………………………………………..…45
Table 4-4: Weight Percent Filler in Factorial Design Formulations……………………..47
Table 4-5: Factorial Design Analysis for the Logarithm of the Electrical Resistivity…..48
Table 4-6: Thermal Conductivity Results for TC307 GNP in Epoxy Composites………49
Table 4-7: Thermal Conductivity Results for Ketjenblack EC-600 JD CB in Epoxy…...50
Table 4-8: Thermal Conductivity Results for Ketjenblack EC-600 JD CB and TC307
GNP in Epoxy……………………………………………………………...…51
Table 4-9: Tensile Results for TC307 GNP in Epoxy Composites……………………...52
Table 4-10: Tensile Results for Ketjenblack EC-600 JD in Epoxy Composites………...54
Table 4-11: Tensile Results for TC307 GNP and Ketjenblack EC-600 JD in Epoxy…...57
Table 5-1: A Summary of the Conclusions Made About the Composite Types Tested…65
Table 5-2: Potential Applications for Composite Formulations Tested for ER………….67
Table A-1: ASTM D257 Through-Plane Electrical Resistivity Results for Neat
Epoxy………………………………………………………………………...72
Table A-2: ASTM D257 Through-Plane Electrical Resistivity Replicate Results for
Neat Epoxy…………………………………………………………………..72
Table A-3: ASTM D257 Through-Plane Electrical Resistivity Results for 5 wt%
TC307 GNP in Epoxy Composites…………………………………………..73
Table A-4: ASTM D257 Through-Plane Electrical Resistivity Replicate Results for 5
wt% TC307 GNP in Epoxy Composites …………………………..………..73
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Table A-5: ASTM D257 Through-Plane Electrical Resistivity Results for 10 wt% TC307
GNP in Epoxy Composites………………………………………..……........74
Table A-6: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for
15 wt% TC307 GNP in Epoxy Composites.....................................................74
Table A-7: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for
20 wt% TC307 GNP in Epoxy Composites.....................................................75
Table A-8: ASTM D257 Through-Plane Electrical Resistivity Results for 0.33%
Ketjenblack EC-600 JD CB in Epoxy Composites ………………...………..75
Table A-9: ASTM D257 Through-Plane Electrical Resistivity Replicate Results for
0.33% Ketjenblack EC-600 JD CB in Epoxy Composites……..……………76
Table A-10: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for 0.67%
Ketjenblack EC-600 JD CB in Epoxy Composites…………………………76
Table A-11: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for 1 wt%
Ketjenblack EC-600 JD CB in Epoxy Composites…………………………77
Table A-12: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for 0.33
wt% Ketjenblack EC-600 JD CB and 5 wt% TC307 GNP in Epoxy
Composites………………………………………………………….………77
Table A-13: ASTM D4496 Two Point In-Plane Electrical Resistivity Replicate Results
for 0.33 wt% Ketjenblack EC-600 JD CB and 5 wt% TC307 GNP in Epoxy
Composites………………………………………………………………….78
Table A-14: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for 0.33
wt% Ketjenblack EC-600 JD CB and 10 wt% TC307 GNP in Epoxy
Composites……………………………………………………………….....78
Table B-1: Thermal Conductivity of Neat Epoxy………………………………………..79
Table B-2: Thermal Conductivity of 5 wt% TC307 GNP in Epoxy Composites………..79
Table B-3: Thermal Conductivity of 10 wt% TC307 GNP in Epoxy Composites………80
Table B-4: Thermal Conductivity of 15 wt% TC307 GNP in Epoxy Composites………80
Table B-5: Thermal Conductivity of 20 wt% TC307 GNP in Epoxy Composites………80
Table B-6: Thermal Conductivity of 0.33 wt% Ketjenblack EC-600 JD CB in Epoxy
Composites…………………………………………………………………...81
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Table B-7: Thermal Conductivity of 0.67 wt% Ketjenblack EC-600 JD CB in Epoxy
Composites…………………………………………………………………...81
Table B-8: Thermal Conductivity of 1 wt% Ketjenblack EC-600 JD CB in Epoxy
Composites…………………………………………………………………...81
Table B-9: Thermal Conductivity of 0.33 wt% Ketjenblack EC-600 JD CB and 5 wt%
TC307 GNP in Epoxy Composites…………………………………………..82
Table B-10: Thermal Conductivity of 0.33 wt% Ketjenblack EC-600 JD CB and 10 wt%
TC307 GNP in Epoxy Composites…………………………………………82
Table C-1: Tensile Results for Neat Epoxy……………………………………………...83
Table C-2: Tensile Results for 5 wt% TC307 GNP in Epoxy Composites……………...84
Table C-3: Tensile Results for 10 wt% TC307 GNP in Epoxy Composites…………….85
Table C-4: Tensile Results for 15 wt% TC307 GNP in Epoxy Composites…………….86
Table C-5: Tensile Results for 20 wt% TC307 GNP in Epoxy Composites…………….87
Table C-6: Tensile Results for 0.33 wt% Ketjenblack EC-600 JD CB in Epoxy
Composites…………………………………………………………………...88
Table C-7: Tensile Results for 0.67 wt% Ketjenblack EC-600 JD in Epoxy
Composites……………………………………………………………….…..89
Table C-8: Tensile Results for 1 wt% Ketjenblack EC-600 JD in Epoxy
Composites……………………………………………………………….…..90
Table C-9: Tensile Results for 0.33 wt% Ketjenblack EC-600 JD CB and 5 wt% TC307
GNP in Epoxy Composites…………………………………………………..91
Table C-10: Tensile Results for 0.33 wt% Ketjenblack EC-600 JD CB and 10 wt%
TC307 GNP in Epoxy Composites…………………………………………92
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Preface
The work contained in this thesis was conducted in the department of Chemical
Engineering at Michigan Technological University from May 2017 to December 2017.
The work done in this thesis has been published in the following article in the Journal of
Composite Materials:
Krieg, A. S., King, J. A., Jaszczak, D. C., Miskoglu, I., Mills, O. P., & Odegard, G. M.
"Tensile and conductivity properties of epoxy composites containing carbon black and
graphene nanoplatelets." Journal of Composite Materials (Copyright © 2018):
0021998318771460. Reprinted by permission of SAGE Publications.
xi
Acknowledgements
I would like to thank my advisor Dr. Julie King for being a good mentor that genuinely
cares about her students. I would also like to give a special thanks to my committee
members, Dr. Gregory Odegard and Dr. Ibrahim Miskioglu, for their guidance and
helpful insights throughout the project.
Additionally, I would like to gratefully thank the NSF I/UCRC on Novel High
Voltage/Temperature Materials and Structures (Grant IIP-1362040) and the Lorna and
James Mack Endowed Chair for funding this project. I also thank the Asbury Carbons
and Akzo Nobel for providing the carbon fillers used in this study. I would also like to
thank Casey Elkins from Flak Tek for assistance in designing the mixing methods used
for this project.
I would also like to thank employees at the Michigan Tech who contributed to this study:
Owen Mills for his fantastic work doing imaging on the field emission scanning electron
microscope and Gerald Anzolone for preparing the specimens for imaging. I must also
thank Jerry Norkol and Steve Winsiewski for their artful resourcefulness in addressing
the technical issues that would arise.
I would also like to thank the following undergraduate students for their assistance on this
project: Nate Baldwin, Sarah Boyd, Anna Hohnstadt, Lexi Fitzpatrick, Emilia Kuemin,
Evan Murphy, Leif Odegard, Rebecca Phipps, Austin Weick, Carson Williams, Charlie
Biyong, and Nick Olson.
Finally, I’d like to thank my family who have always told me that almost anything can be
accomplished if you work hard enough. My father Scott Krieg and mother Rhonda Krieg
for their continued support. I’d like to thank my brother Christopher Krieg for facilitating
my interest in science and for his informed guidance. I’d also like to thank my wife
Karleigh Krieg and son Trez Krieg who inspire me every day to be somebody and to
never give up.
xii
Abstract
Adding carbon fillers to a polymer produces composites with unique conductivity
and tensile properties. Varying amounts of carbon black (CB: < 1 wt%), graphene
nanoplatelets (GNP: < 20 wt%), and combination (0.33 wt% CB with < 10 wt% GNP) of
fillers were compounded in epoxy. The thermal and electrical conductivities and tensile
properties were evaluated. These composites can be used for electrically insulating, static
dissipative, or semi-conductive applications depending on the electrical resistivities (ER).
The 0.33wt% CB/5wt% GNP composite caused the ER to significantly decrease,
which is likely due to the highly branched CB forming conductive networks with GNP.
Concerning single filler composites, adding ≤ 1 wt% CB did not significantly change the
composite tensile properties; however, adding GNP did change tensile properties. One
possible application for the 10 wt% GNP composite is in Polymer Core Composite
Conductors for transmission lines, which require improved thermal conductivity and
mechanical properties.
1
1 Introduction
Composites with varying concentrations of conductive fillers in an insulating
polymer can be used for a variety of applications. After a composite’s electrical
percolation threshold (the point at which the conductivity has significantly increased with
the addition of a small amount of conductive filler) has been reached, it can be used for
static dissipative [electrical resistivity (ER) ranging from ~1010 to 105 ohm-cm] and
semi-conductive (ER ranging from 104 to 10 ohm-cm) applications. If the composites
electrical percolation threshold has not been reached, then the composites can be used for
electrical insulating applications such as Polymer Core Composite Conductors (PCCCs).
PCCCs are used by utility companies to transmit more power over existing electrical
transmission rights-of-ways than traditional transmission lines. The composite core in
PCCCs are used for their high specific strength and stiffness. PCCCs consist of an inner
core comprised of a carbon fiber (CF)/epoxy and a thinner outer shell that consists of
glass fiber (GF)/epoxy. The insulating glass composite material of the outer shell
prevents the electrically conductive carbon composite inner core from transmitting a
current. Since the composite core is considerably lighter than the conventional steel cores
used to reinforce transmission lines, more aluminum strands can be added to increase the
electrical capacity of the lines by a factor of 2[1-3].
Graphene nanoplatelets (GNPs) are short graphitic stacks consisting of individual
layers of graphene that often increase the elastic modulus (stiffness), electrical
conductivity (1/ER), and thermal conductivity of a composite and are available at a
2
relatively low cost (approximately $5-$50/lb) compared to the higher costs of carbon
nanotubes[4-9]. Increasing the composite thermal conductivity can allow these materials
to be used in heat sink applications. Various models have been used to predict the tensile
modulus of GNP in epoxy composites at different filler loading levels. These models
consider the constituent properties, concentrations of each constituent, and the filler
aspect ratio and orientation[7][10-16]. Carbon black (CB) is a cost effective filler (~ $5-
15/lb) that has often been used to increase the electrical conductivity (1/ER) of a
composite[17-19]. An investigation was carried out to determine if the addition of a small
amount of CB to GNP composites with varying filler concentrations of GNP increased
the electrical conductivity more than the additive effect of each filler by itself. The
composite formulations fabricated and tested in this study have not been previously
reported in the open literature.
1.1 References
[1] “Engineering Transmission Lines with High Capacity Low Sag ACCC® Conductors
Manual”. CTC Global. 2026 McGaw Avenue Irvine, CA 92614. (2011).
[2] Hoffman J, Middleton J, and Kumosa, M. “Effect of a surface coating on flexural
performance of thermally aged hybrid glass/carbon epoxy composite rods”. Compos. Sci.
Technol., (2015);106:141-148.
[3] Middleton J, Burks B, Wells T, Setters AM, and Jasiuk I, and Kumosa M. “The effect
of ozone on polymer degradation in Polymer Core Composite Conductors”. Polym.
Degrad. Stabl., (2013);98: 436-445.
[4] XG Sciences Inc. xGnP® Brand Graphene Nanoplatelets Product Information. 3101
Grand Oak Drive, Lansing, MI, (2010).
[5] Kalaitzidou K, Fukushima H, and Drzal, LT. “Mechanical properties and
morphological characterization of exfoliated graphite-polypropylene nanocomposites.
Composites Part A: Applied Science and Manufacturing”, (2007); 38: 1675- 1682.
3
[6] Fukushima H, Drzal LT, Rook BP, and Rich MJ. “Thermal conductivity of exfoliated
graphite nanocomposites”. Journal of Thermal Analysis and Calorimetry, (2006); 85:
235 238.
[7] Kalaitzidou K, Fukushima H, Miyagawa H, and Drzal L T. “Flexural and tensile
moduli of polypropylene nanocomposites and comparison of experimental data to
Halpin-Tsai and Tandon-Weng models”. Polymer Engineering and Science, (2007); 47:
1796-1803.
[8] Kalaitzidou K, Fukushima H, and Drzal LT. “A new compounding method for
exfoliated graphite-polypropylene nanocomposites with enhanced flexural properties and
lower percolation threshold”. Composites Science and Technology, (2007); 67:2045-
2051.
[9] Asbury Carbons, Thermocarb Graphite TC-Series Product Information, 405 Old Main
Street, Asbury, NJ 08802, (2013).
[10] Halpin, J.C., and Kardos, J. L. “The Halpin-Tsai equations: A review”. Polymer
Engineering and Science, (1976); 16: 344-352.
[11] Agarwal B.D. and Broutman L. J. “Analysis and Performance of Fiber
Composites”. Wiley, New York, NY, (1980).
[12] Mallick P. K. “Composites Engineering Handbook”, Marcel Dekker, Inc., New
York, NY, (1997).
[13] Halpin J. C. “Stiffness and Expansion Estimates for Oriented Short Fiber
Composites”. Journal of Composite Materials (1969); 3: 732-734.
[14] Karrad, S, Lopez Cuesta JM., and Crespy A. “Influence of a fine talc on the
properties of composites with high density polyethylene and polyethylene/polystyrene
blends”. Journal of Materials Science (1998); 33: 453- 461.
[15] Jain S, Reddy MM, Mohanty AK, Misra M, and Chosh AK. “A new biodegradable
flexible composite sheet from poly(lactic acid)/poly(ε-caprolactone ) blends and
microtalc”. Macromol. Mater Engr. (2010); 295: 750-762.
[16] Guth E. “Theory of Reinforcement”. Journal of Applied Physics (1945); 16: 20- 25.
[17] Donnet J-B, Bansal R C, and Wang M-J. “Carbon Black”, 2nd edition, New York,
NY: Marcel Dekker, Inc, (1993).
[18] Huang J –C. “Carbon black filled conducting polymers and polymer blends”. Adv.
Polym. Technol. (2002); 21, 299-313.
4
[19] Akzo Nobel Electrically Conductive Ketjenblack Product Literature, 300. S.
Riverside Plaza, Chicago, IL, (1999).
5
2 Materials
2.1 Materials
For this project there were two carbon fillers used in an epoxy matrix that were
studied. The carbon fillers assessed in the study were Asbury Carbons TC307 graphene
nanoplatelets and Akzo Nobel Ketjenblack EC-600 JD carbon black. The thermoset
polymer system used as the matrix was Hexions EPON™ Resin 862 with EPIKURE™
Curing Agent W.
2.2 Matrix Material
The epoxy matrix used in this study is a phenolic glycidyl ether resin, Hexion’s
EPON™ 862 (diglycidyl ether of bisphenol F, DGEBPF) that is cured with an amine
hardening agent, EPIKURE Curing Agent W (diethyltoluenediamine, DETDA). EPON™
Resin 862 is a low viscosity liquid epoxy resin manufactured from the condensation
reaction between epichlorohydrin and the phenol group on bisphenol F. The reaction that
produces EPON Resin 862 is shown in Figure 2-1. The viscosity of EPON™ Resin 862
at 25°C is ~35 P. EPIKURE™ Curing Agent W is an aromatic diamine with a viscosity
of ~200 cP [1]. The molecular structure of EPIKURE™ Curing Agent W is shown in
Figure 2-2.
6
Epichlorohydrin Bisphenol F EPON™ Resin 862
Figure 2-1: Formation of EPON™ Resin 862 from Epichlorohydrin and Bisphenol F -
drawn from reaction given in vendor literature
EPIKURE™ Curing Agent W
Figure 2-2: EPIKURE™ Curing Agent W Structure
EPON™ Resin 862/EPIKURE™ W is a thermoset epoxy system with a curing
cycle of 121°C for 2 hours followed by 177°C for 2 hours. The formation of the cured
thermoset system results from the epoxide groups on the EPON™ Resin 862 reacting
with the amine groups on the EPIKURE™ Curing Agent W. As the reaction progresses,
the system becomes a branched crosslinked structure as shown in Figure 2-3. The cured
EPON™ Resin 862/EPIKURE™ W system has a density of 1.20 g/cm³ [1].
7
EPON™ Resin 862 EPIKURE™ W EPON™ Resin 862 + EPIKURE™ W
EPON™ Resin 862 EPON™ Resin 862 + EPIKURE™ W
Figure 2-3: Crosslinking of EPON™ Resin 862 with EPIKURE™ Curing Agent W
8
2.3 Filler Materials
2.3.1 Asbury Carbons TC307 Graphene Nanoplatelets
Graphene nanoplatelets consist of small stacks of graphene sheets. Each graphene
sheet is a single layer of graphite with the structure seen in Figure 2-4. GNP’s are
available in a variety of particle sizes and surface modifications.
Figure 2-4: Structure of Graphene Nanoplatelets
The graphene nanoplatelets used in this study are Asbury Carbons TC307 grade,
which is a high purity synthetic graphite that is manufactured using a proprietary
technique. TC307 GNP are composed of platelets with a mean particle diameter of <1 μm
and a thickness of ~10-15 nm. The graphene nanoplatelets are comprised of
approximately 8 layers, a specific gravity of 2 and have a mean BET surface area of 350
m²/g. The graphene is electrically conductive and has a resistivity of 0.26 ohms-cm [2].
9
2.3.2 Akzo Nobel EC-600 JD Carbon Black
The carbon black used in this study is Akzo Nobel’s Ketjenblack EC-600 JD
which is an electrically conductive carbon black that consists mainly of elemental carbon
in the form of spherically shaped particles that have been fused together to form
aggregates. Ketjenblack EC-600 JD is a carbon black with a highly branched structure
that enables the formation of electrical networks across the polymer matrix with
relatively low concentrations of carbon black. Due to the unique morphology of
Ketjenblack EC-600 JD carbon black, only 1/6 of the amount is required to achieve the
same conductivity of conventional electroconductive carbon blacks [3].
Ketjenblack EC-600 JD carbon black has a density of 1.8 g/cm³ and an electrical
resistivity of 0.01-0.1 ohm-cm. The carbon black pellets range between 100 μm and 2
mm in size and consist of primary aggregates that range from 30-100 nm in size. The
Ketjenblack EC-600 JD has a Brunauer-Emmett-Teller (BET) surface area of 1,250 m²/g.
The aggregates have a pore volume between 480-510 cm³/100g [3]. The morphology of
carbon black aggregates can be seen in Figure 2-5.
Figure 2-5: Structure of Carbon Black Aggregate [3]
10
2.4 Formulation Naming Convention
A naming convention was generated to organize the samples in a relatively simple
and unique way that allows the specimens to be individually identified and distinguished
from one another. Each sample was numbered and labeled according to the constituents
of the composite and the date of its fabrication. The naming system is as follows:
U 862 – a b – cd - date - e
Where:
U = project description
862 = EPON™ Resin 862
a = weight percent of filler, if there are no fillers in the composite then this entry is
omitted
b = filler type (T= Asbury Carbons TC307 GNP, A=Akzo Nobel Ketjenblack EC-600
JD), if there are no fillers in the matrix then this entry is omitted
c = weight percent of second filler, if there are no fillers in the matrix or it is a single
filler composite then this entry is omitted
d = second filler type (T = Asbury Carbons TC307 GNP, A=Akzo Nobel Ketjenblack
EC-600 JD), if there are no fillers in the matrix or it is a single filler composite then this
entry is omitted
e = specimen number
11
2.5 References
[1] Hexion EPON™ Resin 862/EPIKURE™ Curing Agent W Product Literature, 180
Broad St, Columbus, OH 43215. (2017).
[2] Asbury Carbons Synthetic Graphite Product Literature, 405 Old Main St., Asbury, NJ
08802. (2015).
[3] Akzo Nobel Electrically Conductive Ketjenblack Product Literature, 300 S. Riverside
Plaza, Chicago, IL, 60606. (1999).
12
3 Fabrication and Experimental Methods
3.1 Fabrication Methods
A FlackTek SpeedMixer DAC 150.1 FVZ, shown in Figure 3-1, was used to
disperse the carbon fillers randomly across the matrix. The FlackTek SpeedMixer is a
bladeless high-shear mixer that uses centrifugal forces to achieve a uniform dispersion.
The DAC 150.1 FVZ model has a weight capacity of 100 g per cup and holds a single
cup at a time.
Figure 3-1: SpeedMixer
Figure 3-1: FlackTek SpeedMixer DAC 150.1 FVZ
Mixing methods for GNP and CB composite materials were determined by trial
and error through coordinated efforts with FlackTek Inc. technicians. The concentration
of filler in the master batch was chosen to achieve a viscosity similar to that of peanut
butter at 23 °C. The mixing method for each type of composite was determined once
13
material consistency had been achieved. In the case of each type of composite, fillers
were loaded in incremental concentrations until it was too viscous to pour into steel
rectangular- and disk-molds shown in Figure 3-2. The steel rectangular disk molds
produce 20 bars (165 mm long by 19 mm wide by 3.3 mm thick) and the steel disk molds
produce 5 disks (64 mm diameter and 3.2 mm thick). Table 3-1 shows the concentrations
(shown in wt% and the corresponding vol%) for the composite formulations tested in this
study.
Figure 3-2: (left) Steel Rectangular Disk Molds, (right) Steel Disk-Molds
14
Table 3-1: Filler Loading Levels in Epoxy
Formulation Filler Content
wt% (vol%)
Neat 0.0 (0.0)
GNP
5.0 (3.1)
10.0 (6.3)
15.0 (9.6)
20.0 (13.0)
CB
0.33 (0.22)
0.67 (0.44)
1.0 (0.67)
GNP/CB
CB: 0.33 (0.20) GNP: 5.0 (3.1)
CB: 0.33 (0.20) GNP: 10.0 (6.3)
The epoxy/amine system used in this study was degassed and cured in a Fisher
Isotemp® Vacuum Oven Model 282A with a Welch 1402 DuoSeal® Vacuum Pump,
shown in Figure 3-3. The cure cycle was obtained from the polymer systems product
literature. The finalized mixing procedures and cure cycles are described in the following
subsections. For this entire project, each batch yielded a total of 450 g of material
obtained by 5 mixing cups which each contained 90 g of the material. Also, a ratio of 100
g of epoxy was added to 26.4 g of hardener to prepare the polymer matrices used
throughout this project [1] A 450 g batch of material makes 20 rectangular bars (165 mm
long by 19 mm wide by 3.3 mm thick) and 5 disks (64 mm diameter and 3.2 mm thick).
15
Figure 3-3: Fisher Isotemp® Vacuum Oven Model 282A with a Welch 1402 DuoSeal®
Vacuum Pump
3.1.1 Neat Epoxy Test Specimen Fabrication
To manufacture the neat epoxy samples, 100 g of EPON™ 862 was added to 26.4
g of EPIKURE Curing Agent W. The mixture was mixed by hand for 3 min at 23°C. The
mixture was then degassed inside an oven at 90°C and 29 inches Hg vacuum for 30 min
and poured into a rectangular shaped mold (165 mm long by 19 mm wide by 3.3 mm
thick). The curing cycle for this aerospace epoxy resin was 121°C for 2 h followed by 2 h
at 177°C. Samples were allowed to cool to ambient temperature before being removed
from the mold [2].
16
3.1.2 TC307 GNP/Epoxy Test Specimen Fabrication
To manufacture the GNP/epoxy composites, master batches of 30 wt% GNP were
compounded by adding the appropriate amount of TC307 GNP on top of EPON™ 862
epoxy resin in a mixing cup. The epoxy resin and GNP were mixed for a total of 2.5 min
at 3,000 rpm in a FlackTek SpeedMixer DAC 150.1 FVZ.
The mixed masterbatch was diluted to achieve the desired amount of filler in each
formulation. Neat epoxy resin, masterbatch, and hardener were poured into mixing cups
and mixed at 2,250 rpm for 3 min in the SpeedMixer. The material was degassed in the
mixing cups at 90 °C and 29 inches Hg vacuum for 35 min. Rectangular- and disc-
shaped steel molds were coated with Mann Ease Release 300, then assembled and
preheated in an oven at 90 °C. The degassed mixture was then poured into the steel molds
and degassed again for another 35 minutes.
The fully degassed material was cured in an oven by heating the mold to 121 °C
and holding it at that temperature for 2 hours followed by raising the temperature of the
oven to 177 °C and sustaining that temperature for an additional 2 hours. The oven was
then turned off and the cured epoxy was allowed to cool to ambient temperature in the
oven at an average cooling rate of 1 °C/min. Twenty rectangular bars (3.2 mm thick by
165 mm long by 19 mm wide) and 5 disks (64 mm diameter and 3.2 mm thick) were
fabricated per each batch using this method.
17
3.1.3 Ketjenblack EC-600 JD CB/Epoxy Test Specimen Fabrication
To manufacture the CB/epoxy composites, master batches of 5 wt% CB were
compounded by adding the appropriate amount of EC-600 JD CB on top of EPON™ 862
epoxy resin in a mixing cup. The epoxy resin and CB were mixed for 1.5 min at 2,500
rpm in a FlackTek SpeedMixer DAC 150.1 FVZ. Four zirconium mixing cylinders were
placed into the cup and the cups were mixed 3 times for 1.5 minutes at 2,500 rpm in the
SpeedMixer while allowing to cool back to ambient temperature after each time the cups
were mixed.
The mixed masterbatch was diluted to achieve the desired amount of filler in each
formulation. Neat epoxy resin, masterbatch, and hardener were poured into mixing cups
and mixed twice at 3,500 rpm for 1.5 min in the SpeedMixer. The walls on the inside of
the cups were scraped and mixed by hand in between mixes. Rectangular- and disc-
shaped steel molds were coated with Mann Ease Release 300, then assembled and
preheated in an oven at 90°C. The mixture was then poured into the steel mold and
degassed for 35 minutes. The same curing cycle was used as described for the
GNP/epoxy composites. Twenty rectangular bars (3.2 mm thick by 165 mm long by 19
mm wide) and 5 disks (64 mm diameter and 3.2 mm thick) were fabricated using this
method.
18
3.1.4 TC307 GNP/Ketjenblack EC-600 JD CB/Epoxy Test Specimen Fabrication
To manufacture the GNP/CB/epoxy composites, masterbatches of GNP and CB
were fabricated using the same procedure described for the GNP/epoxy and CB/epoxy
composites. The appropriate amount of GNP and CB masterbatches were combined and
diluted to achieve the desired amount of fillers in each formulation. Neat epoxy resin,
masterbatch, and hardener were poured into mixing cups and mixed twice at 3,500 rpm
for 1.5 min in the SpeedMixer. The walls on the inside of the cups were scraped and
mixed by hand in between mixes. Rectangular- and disc- shaped steel molds were coated
with Mann Ease Release 300, then assembled and preheated in an oven at 90°C. The
mixture was then poured into the steel mold and degassed for 35 minutes. The same
curing cycle was used as described for the GNP/epoxy composites. Twenty rectangular
bars (3.2 mm thick by 165 mm long by 19 mm wide) and 5disks (64 mm diameter and
3.2 mm thick) were fabricated using this method.
3.2 Experimental Test Methods
3.2.1 Field Emission Scanning Electron Microscopy (FESEM) Test Method
A Hitachi S-4700 field emission scanning electron microscope (FESEM), shown
in Figure 3-4, was used to image GNP/epoxy and CB/epoxy composite samples. FESEM
is useful for high resolution imaging. The upper secondary electron detector was used to
collect high resolution images of the samples surface topology.
19
Figure 3-4: Hitachi S-4700 field emission scanning electron microscope (FESEM)
The GNP in epoxy samples were prepared for FESEM by cutting small cubes
from the tested tensile specimen using a Delta Shopmaster 16” Variable Speed Scroll
Saw with Quickset II Blade Changing Feature Model SS350, as shown in Figure 3-5. The
samples were cut with dimensions of approximately 3 mm long so that the tensile fracture
surface would be viewed. The samples were blown with a pressurized air nozzle to
remove residual particles from the saw and then were placed tensile fracture surface up
on an aluminum sample mount before being sputtered with a 2nm thick
platinum/palladium coating using a Cressington 208HR High Resolution Sputter Coater,
shown in Figure 3-6. The film thickness was measured with a Cressington MTM-20
Thickness Controller, also shown in Figure 3-6. The accelerating voltage was set to 2.0
kV at a working distance of 13.6 mm.
20
Figure 3-5: Delta Shopmaster 16” Variable Speed Scroll Saw with Quickset II Blade
Changing Feature Model SS350
Figure 3-6: Cressington 208HR High Resolution Sputter Coater with a Cressington
MTM-20 Thickness Controller
21
CB in epoxy samples were mounted and polished to perform microscopic
analysis. To view the CB in epoxy, the following sample preparation method was used.
First, the 1 wt% CB/epoxy composite samples were mounted in an epoxy puck. The
tensile fracture surface was placed in the bottom of 1.25” metallographic mount molds
and placed into a Logitech vacuum impregnator, shown in Figure 3-7. While the
specimen chamber was evacuated, Epotek 301 epoxy was prepared and mixed. Epotek
301 epoxy is a two-component room temperature curing epoxy available from Epoxy
Technology, Inc. with a relatively low viscosity of 100-200 cPs at 23 °C. Part A of the
Epotek 301 epoxy consists of diglycidyl ether of bisphenol A (DGEBPA) and a
proprietary reactive diluent. Part B of the system is trimethyl-1,6-hexanediamine [3]. The
epoxy was then vacuum degassed and introduced to the specimen chamber while still
under vacuum. Upon filling the mold with liquid epoxy, the specimen chamber was
returned to ambient pressure and the filled mold was removed and placed in a desiccator
to cure for 24 hours at 25 °C.
Figure 3-7: Logitech Vacuum Impregnator
22
Table 3-2 shows the grinding and polishing steps. After removing the epoxy-
impregnated specimen, the sample was ground using a Struers LaboForce-3
metallographic specimen grinder/polisher, shown in Figure 3-8. The grinder was fitted
with pressure sensitive adhesive PSA-backed #400 grit fixed SiC grinding disks and was
ground at 250 rpm with a force of 5 N until the surface of the mount was flat. Grinding
continued at 250 rpm with #800 and #1500 grit PSA-backed fixed SiC media for 2
minutes each and the sample surface was exposed.
Table 3-2: Grinding and Polishing Steps
Surface Lubricant Abrasive Time Force RPM Direction
SiC - 400 grit Water SiC - 400 grit Till plane 5 N 250 Contra
SiC - 800 grit Water SiC - 800 grit 2 min 5 N 250 Contra
SiC - 1500 grit Water SiC - 1500 grit 2 min 5 N 250 Contra
Hudcloth Red Soln. METADI Supreme
9 μm 15 sec - 250 Contra
Hudcloth Green Soln. METADI Supreme
3 μm 15 sec - 250 Contra
Hudcloth White Soln.
Alumina Suspension
1 μm 15 sec - 250 Contra
Hudcloth Water Diamond Paste
0.25 μm 1 hour - - -
Hudcloth White Soln. Master Prep
0.05 μm 1 hour - - -
23
Figure 3-8: Struers LaboForce-3 metallographic specimen grinder/polisher
A Buehler EcoMet 4 Rotary Polisher, shown in Figure 3-9, was fitted with an
abrasive Hudcloth nap cloth and used to remove scratches made from grinding. The flat
surface of the puck was polished by hand using multi-crystalline diamond, starting with
METADI Supreme 9 µm media, METADI Supreme 3 µm media, and then 1 µm alumina
suspension media all while rotating at 250 rpm and for 15 seconds with each media.
24
Figure 3-9: Buehler EcoMet 4 Rotary Polisher
Intermediate and final polishing were completed on a Buehler VibroMet I
Vibratory Polisher, shown in Figure 3-10, fitted with a Hudcloth nap cloth. 0.25 µm
diamond paste and 0.05 µm colloidal silica polishing suspension were used for
intermediate and final polishing, respectively for an hour each. The specimens were
cleaned between each grinding and polishing step by sonicating for five minutes in
distilled water. Water was used for the lubricant throughout the grinding and polishing
steps.
25
Figure 3-10: Buehler VibroMet I Vibratory Polisher
The polished composite surface was dry etched in a March Jupiter II parallel plate
reactive ion etcher, shown in Figure 3-11. The composite was etched with oxygen plasma
at 100 standard cm³/min of 𝑂2 for 5 min. The etching was done at low pressure, 249
mTorr, and at 300 W. The sample was sputter coated with a layer of Pt/Pd with a
thickness of approximately 5 nm using a Cressington 208HR high resolution sputter
coater. Coating thickness was measured with a Cressington MTM-20 film thickness
controller. Images were acquired with the Hitachi S4700 field emission scanning
electron microscope (FESEM). The microscope was operated at 10 kV of accelerating
voltage with a 10 μA emission current. The working distance was 6.3 mm using the
upper secondary electron detector.
26
Figure 3-11: March Jupiter II Reactive Ion Etcher
3.2.2 Through-Plane Electrical Resistivity Test Method
Through-plane volumetric electrical conductivity tests were conducted at 23 °C
on as-molded disk samples with an electrical resistivity greater than 107 ohm-cm in
accordance with ASTM D257 [4]. The electrical resistivity was measured by applying a
constant voltage (typically 100 V) to the test specimen using a Keithley 6517A
Electrometer/High Resistance Meter and an 8009 Resistivity Test Fixture, as shown in
Figure 3-12. Figure 3-13 shows a picture illustrating this apparatus. Keithley 6524 High
Resistance Measurement Software was used to automate the conductivity measurement.
A minimum of five specimens were tested for each formulation. The test specimens were
from the molded disk that was 6.4 cm in diameter and 3.2 mm thick. The samples were
conditioned at 23 °C and 50% relative humidity for two days prior to testing.
27
Figure 3-12: (left) Keithley 6517A Electrometer/High Resistance Meter, (right)
Keithley 8009 Resistivity Test Fixture
Figure 3-13: Diagram of Through Plane Electrical Resistivity Test
3.2.3 In-Plane Electrical Resistivity Test Method
In-plane volumetric electrical conductivity tests were conducted at 23 °C on
rectangular samples with an electrical resistivity of less than 107 ohm-cm in accordance
28
with ASTM D4496 [5]. The test samples were prepared by scratching a 3.2 mm thick, 19
mm wide and 60 mm long rectangular sample with a razor blade, placing the sample in
liquid nitrogen, and manually breaking the cryogenic sample at the desired locations,
which produced a fracture surface at each end of the in-plane sample. The 3.2 mm thick
by 19 mm fracture surfaces were coated with silver paint and dried for one hour. The
electrical resistivity was measured by using two probes to conduct the tests on the
samples by placing one probe on each silver painted fracture surface and applying a
constant voltage to the sample using a Keithley 2400 Source Meter, shown in Figure 3-
14. The current flowing across the sample was measured on the source meter. At least 5
samples were tested for each formulation. The electrical resistivity was calculated using
Equation 3-1. The samples were conditioned at 23 °C and 50% relative humidity for two
days prior to testing.
Figure 3-14: Keithley 2400 Source Meter
29
𝐸𝑅 = (∆𝑉)(𝑤)(𝑡)
(𝑖)(𝐿) [3-1]
where:
ER = Electrical Resistivity, ohm-cm
∆V = Voltage drop, volts
w = sample width, cm
t = sample thickness, cm
i = current, amps
L = length over which ∆V is measured
3.2.4 Thermal Conductivity: Guarded Heat Flow Meter Test Method
The through-plane thermal conductivity of disk samples was measured at 55 °C
using a Netzsch Model TCA 300 Thermal Conductivity Analyzer, shown in Figure 3-15.
The test samples were prepared by grinding 3.2 mm thick disks to a 5 cm diameter using
the circle grinder, shown in Figure 3-16.
30
Figure 3-15: Netzsch Model TCA 300 Thermal Conductivity Analyzer
Figure 3-16: Circle Grinder
31
The samples were tested in accordance with the ASTM F433 guarded heat flow
method [6]. The thermal conductivity was measured at 55 °C because this temperature
was as close to ambient temperature as could be measured while still maintaining a
temperature gradient in the apparatus. Figure 3-17 shows a diagram of the test method
used to measure through-plane thermal conductivity [7]. For each formulation, at least
four samples were tested. The samples were conditioned at 23 °C and 50% relative
humidity for two days prior to testing.
Figure 3-17: Diagram of Through-Plane Thermal Conductivity Test Method [7]
3.2.5 Mechanical Tensile Property Test Method
Specimens were tested for tensile properties at 23 °C according to ASTM D638
and ASTM Type I sample geometry: 65 mm long by 3.2 mm thick [8]. A Ceast router,
shown in Figure 3-18, was used to grind the specimens into dog-bone shaped samples
with a width of 12.6 mm. For each formulation, at least 5 samples were tested at a
32
crosshead rate of 1 mm/min using a Tinus Olsen hydraulic mechanical testing machine,
shown in Figure 3-19. Stress values are recorded by the testing machine and an axial
extensometer from Epsilon Technology Corporation that was used to collect the strain
values. Tensile modulus was determined from the initial slope of the stress-strain curve.
For each formulation, at least 5 samples of each composite were tested. The samples were
conditioned at 23 °C and 50% relative humidity for two days prior to testing.
Figure 3-18: Ceast Router
33
Figure 3-19: Tinus Olsen Hydraulic Mechanical Testing Machine With Epsilon Axial
Extensometer
3.3 References
[1] Hexion EPON™ Resin 862/EPIKURE™ Curing Agent W Product Literature. 180
Broad St, Columbus, OH 43215. (2017).
[2] Klimek-McDonald DR, King JA, Miskioglu I, Pineda EJ, and Odegard GM.
“Determination and modeling of mechanical properties for graphene nanoplatelet/epoxy
composites”. Polymer Composites (2016): 10.1002/pc.24137.
[3] Epoxy Technology, Inc. EPO-TEK® 301 Product Literature, 14 Fortune Drive,
Billerica, MA 01821. (2016).
[4] Standard Test Methods for DC Resistance or Conductance of Insulating Materials,
ASTM Standard D257-91, American Society for Testing and Materials, Philadelphia, PA
(1998).
[5] Standard Test Methods for DC Resistance or Conductance of Moderately Conductive
Materials, ASTM Standard D4496-04, American Society for Testing and Materials,
Philadelphia, PA. (2008).
[6] Standard Test Methods for Evaluating Thermal Conductivity of Gasket Materials,
ASTM Standard F433, American Society for Testing and Materials, Philadelphia, PA
(2008).
34
[7] Operation & Maintenance Manual, Holometrix Model TCA-300, 25 Wiggins Ave,
Bedford, MA 01730. (1997).
[8] Standard Test Methods for Tensile Properties of Plastics, ASTM Standard D638,
American Society for Testing and Materials, Philadelphia, PA (2008).
35
4 Results
4.1 Microscopy Results
4.1.1 Asbury Carbon’s TC307 GNP in Epoxy Microscopy Results
A Hitachi S-4700 field emission scanning electron microscope (FESEM) was
used to image GNP/epoxy composite samples. The specimens viewed were 5 wt% and 10
wt% TC307 GNP in epoxy. The microscope was operated at 2 kV of accelerating voltage
and at magnifications of x10,000, and x30,000. Figure 4-1 shows a FESEM image of a
tensile fracture surface for 5 wt% TC307 GNP in epoxy at a magnification of x10,000.
The figure shows TC307 GNP scattered throughout the matrix and demonstrates a three-
dimensional random orientation of TC307 in the epoxy composite. Figure 4-2 is a
FESEM image of the same fracture surface using a magnification of x30,000. The figures
show the platelets to be <1 μm in diameter.
Figure 4-1: Field emission microscope micrograph of 5 wt% TC307 GNP in epoxy at
x10,000 magnification
36
Figure 4-2: Field emission microscope micrograph of 5 wt% TC307 GNP in epoxy at
x30,000 magnification
Figure 4-3 shows a FESEM image of a tensile fracture surface for 10 wt% TC307 GNP in
epoxy at a magnification of x10,000. The figure also demonstrates a uniform three-
dimensional random orientation of TC307 in the epoxy composite. Figure 4-4 is a
FESEM image of the same fracture surface using a magnification of x30,000 and shows
more platelets with diameters of <1 μm.
37
Figure 4-3: Field emission microscope micrograph of 10 wt% TC307 GNP in epoxy at
x10,000 magnification
Figure 4-4: Field emission microscope micrograph of 10 wt% TC307 GNP in epoxy at
x30,000 magnification
38
4.1.2 Akzo Nobel’s Ketjenblack EC-600 JD CB in Epoxy Microscopy Results
A Hitachi S-4700 field emission scanning electron microscope (FESEM) was used to
image CB/epoxy composite samples. The microscope was operated at 10kV of
accelerating voltage and at magnifications of x50,000, x100,000, and x200,000. Figure 4-
5, Figure 4-6, and Figure 4-7 show FESEM images of tensile fracture surfaces for 1 wt%
Ketjenblack EC-600 JD CB in epoxy at magnifications of x50,000, x100,000 and
x200,000, respectively. The images show a network formation of primary aggregates
with sizes between 30-100 nm.
Figure 4-5: Field emission microscope micrograph of 1 wt% EC-600 JD in epoxy at
x50,000 magnification
39
Figure 4-6: Field emission microscope micrograph of 1 wt% EC-600 JD in epoxy at
x100,000 magnification
Figure 4-7: Field emission microscope micrograph of 1 wt% EC-600 JD in epoxy at
x200,000 magnification
40
4.2 Electrical Resistivity Results
4.2.1 Asbury Carbon’s TC307 GNP in Epoxy Electrical Resistivity Results
Table 4-1 shows the ER results for neat epoxy as well as 5, 10, 15 and 20 wt %
GNP in epoxy composites produced and tested in this project. Figure 4-8 shows the ER
results by plotting the log (electrical resistivity in Ω-cm) as a function of the filler volume
fraction. All of the ER data obtained from test specimens were displayed in the graph.
Filler concentrations of 5 and10 wt% TC307 resulted in an electrical resistivity similar to
the values obtained from neat epoxy specimens.
A percolation threshold of ~7 vol% (12 wt%) TC307 GNP was observed in the
data. The percolation threshold is the point where the electrical resistivity of the
composite significantly decreases over a narrow filler concentration differential. The
complete electrical conductivity results can be found in Appendix A. Adding up to 20
wt% TC307 GNP resulted in a decrease in ER from 2.88 × 1016 Ω-cm for the neat epoxy
to 6.05 × 105 Ω-cm. Both 5 and 10 wt% TC307 GNP in epoxy composites can be used
in electrically insulating applications. The 15 and 20 wt% TC307 GNP in epoxy
composites can be used in static dissipative applications (electrical resistivities of ~1010
to 105 Ω-cm).
Wang et al. has reported a percolation threshold of ~2 wt% GNP produced by
Ningbo Institute of Materials Technology and Engineering in a matrix of Dow 6105
cycloaliphatic epoxy cured with a methyl-hexahydrophthalic anhydride monomer [1]. A
41
percolation threshold of ~5 wt% XG Science’s M25 GNP with an average particle
diameter of 25 μm and thickness of 6 nm was observed by Prolongo et al. in an Araldite
LY556 DGEBPA epoxy matrix cured with an XB3473 amine hardener [2].
Chandrasekaran et al. observed a percolation threshold of ~0.25% GNP from Punto
Quantico with a thickness of 13 nm and a diameter of 35 μm in an Araldite LY556
DGEBPA epoxy resin cured with an Aradure 917 anhydride hardener in a solvent based
fabrication method, different from the fabrication process used in this study [3].
Table 4-1: Electrical Resistivity Results for TC307 GNP in Epoxy Composites
Formulation
Filler Content
wt% (vol%)
Electrical Resistivity (ohm-cm)
Standard Deviation (ohm-cm) Count
Neat Epoxy 0 (0) 2.88E+16 3.20E+15 6
Neat Epoxy Replicate 0 (0) 1.85E+16 2.91E+14 6
5 wt% TC307 5.0 (3.1) 1.40E+16 9.36E+14 5
5 wt% TC307 Replicate 5.0 (3.1) 1.42E+16 1.76E+15 5
10 wt% TC307 10.0 (6.2) 9.41E+15 7.46E+14 5
15 wt% TC307 15.0 (9.6) 7.42E+06 3.72E+06 7
20 wt% TC307 20.0 (13.0) 6.05E+05 1.34E+05 5
42
Figure 4-8: Log (electrical resistivity) results for TC307 GNP/epoxy composites
4.2.2 Akzo Nobel’s Ketjenblack EC-600 JD CB in Epoxy Electrical Resistivity Results
Table 4-2 shows the ER results for neat epoxy as well as 0.33, 0.67, and 1.00 wt%
CB in epoxy composites produced and tested in this project. Figure 4-9 shows the ER
results by plotting the log (electrical resistivity in Ω-cm) as a function of the filler volume
fraction. All of the ER data obtained from test specimens were displayed in the graph. A
filler concentration of 0.33 wt% Ketjenblack EC-600 JD CB resulted in an electrical
resistivity similar to the values obtained from neat epoxy specimens.
A percolation threshold of ~0.3 vol% Ketjenblack EC-600 JD was observed in the
data. The CB electrical percolation threshold is very low due to the highly branched and
high surface area structure of Ketjenblack EC-600 JD CB. The complete electrical
conductivity results can be found in Appendix A. The 0.33 wt% Ketjenblack EC-600 JD
0
2
4
6
8
10
12
14
16
18
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14
Lo
g E
lect
rica
l R
esis
tivit
y,
(ohm
-cm
)
GNP Volume Fraction
43
CB in epoxy composites can be used for electrically insulating applications. The 0.67 and
1.00 wt% EC-600 JD CB in epoxy composites can be used for semi-conductive
applications (electrical resistivities of ~101 to 104 Ω-cm).
Lu et al. reported a percolation threshold of 4 wt% CB from Nanyang Carbon
Limited Company with primary aggregate sizes of 100-400 nm in a DGEBPA epoxy
solidified with a low molecular weight polyamide of 650 type using in situ
polymerization [4]. A percolation threshold of ~5 wt% furnace black CB with primary
particle sizes of 3 μm was observed by Abdel-Aal et al. in a Epikot 828 epoxy resin with
an 8 wt% glycerol plasticizer and cured with a Kayo 128 aromatic hardener [5]. Etika et
al. observed a percolation threshold of ~0.5 wt% of Columbian Chemicals Conductex
7055 Ultra CB with a primary particle size of 42 nm in a Dow Chemical D.E.R. 354
epoxy cured with a Dixie Chemicals ECA 100 curing agent [6].
Table 4-2: Electrical Resistivity Results for Ketjenblack EC-600 JD CB in Epoxy
Composites
Formulation
Filler Content
wt% (vol%)
Electrical Resistivity (ohm-cm)
Standard Deviation (ohm-cm) Count
Neat Epoxy 0 (0) 2.88E+16 3.05E+15 6
Neat Epoxy Replicate 0 (0) 1.85E+16 2.91E+14 6
0.33 wt% EC-600 JD 0.33 (0.22) 2.50E+14 1.30E+14 5
0.33 wt% EC-600 JD Replicates 0.33 (0.22) 2.93E+14 1.32E+14 5
0.67 wt% EC-600 JD 0.67 (0.44) 6.44E+03 1.61E+03 6
1.00 wt% EC-600 JD 1.0 (0.67) 7.56E+02 5.44E+01 6
44
Figure 4-9: Log (Electrical Resistivity) Results for Ketjenblack EC-600 JD CB/Epoxy
Composites
4.2.3 TC307 GNP and Ketjenblack EC-600 JD CB in Epoxy Electrical Resistivity Results
Table 4-3 shows the ER results for neat epoxy as well as 0.33 wt% CB/5 wt%
GNP and 0.33 wt% CB/10 wt% GNP in epoxy composites produced and tested in this
project. Figure 4-10 shows the ER results by plotting the log (electrical resistivity in Ω-
cm) as a function of the total filler volume fraction (CB and GNP). All of the ER data
obtained from test specimens were displayed in the graph. Both formulations, 0.33 wt%
CB/5 wt% GNP and 0.33 wt% CB/10 wt% GNP, resulted in electrically conductive
composites.
After adding only a small amount of Ketjenblack EC-600 JD (0.33 wt%) to the 5
and 10 wt% TC307 in epoxy formulations, a dramatic decrease in electrical resistivity
0
2
4
6
8
10
12
14
16
18
0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008
Lo
g E
lect
rica
l R
esis
tivit
y,
(ohm
-cm
)
CB Volume Fraction
45
was observed. Adding 0.33 wt% CB to the 5 wt% GNP composites decreased the
electrical resistivity from 1.4 x 1016 Ω-cm to 1.5 x 104 Ω-cm. Adding 0.33 wt% CB to
the 10 wt% GNP composites further decreased the electrical resistivity from 9.4 x 1015
Ω-cm to 6.4 x 103 Ω-cm. The complete electrical conductivity results can be found in
Appendix A. Both hybrid composite formulations can be used for semi-conductive
applications (electrical resistivities of ~101 to 104 Ω-cm). An ER of 107 Ω-cm was
reported by Fan et al. for a composite containing 0.9 wt% GNP with 270 μm diameter
from Qingdao Graphite Company and 0.1 wt% Ketjenblack EC-600 JD CB in an E44
BPA epoxy resin supplied by Wuxi Resin Factory cured with a dicyandiamide curing
agent supplied by Tianjin Chemical Reagent No. 6 Factory [6].
Table 4-3: Electrical Resistivity Results for Ketjenblack EC-600 JD CB/TC307 GNP in
Epoxy Composites
Formulation
Filler Content
wt% (vol%)
Electrical Resistivity (ohm-cm)
Standard Deviation (ohm-cm) Count
Neat Epoxy 0 (0)
2.88E+16 3.05E+15 6
Neat Epoxy Replicate 0(0)
1.85E+16 2.91E+14 6
0.33 wt% EC-600 JD and 5 wt% TC307
CB: 0.33 (0.22) GNP: 5.0 (3.1) 1.56E+04 1.87E+03 6
0.33 wt% EC-600 JD and 5 wt% TC307 Replicate
CB: 0.33 (0.22) GNP: 5.0 (3.1) 1.44E+04 2.40E+03 6
0.33 wt% EC-600 JD and 10 wt% TC307
CB: 0.33 (0.22) GNP: 10.0 (6.2) 6.40E+03 1.88E+03 5
46
Figure 4-10: Log (Electrical Resistivity) Results for Ketjenblack EC-600 JD/TC307
epoxy composites
4.2.4 Determining Synergistic Effects of Multiple Fillers on Electrical Resistivity
The combinations of EC-600 JD CB and TC307 in epoxy produced significantly
lower ER values than either CB or GNP did by themselves. Factorial designs are the most
efficient way to determine the effect of each filler and to investigate potential interactions
between fillers. By using factorials, the effect of each factor on the electrical resistivity of
the composite can be quantified by a calculated “effect”. The effects of each factor can be
compared to determine which of the filler and combination of fillers produced a larger
change in the electrical resistivity values of the composite material [7]. A two-factor two-
level factorial design with a replicate was administered with low and high loadings of CB
and GNP to determine the individual and synergistic effects of both fillers. A complete
set of replicate formulations were produced for each formulation in order to verify
0
2
4
6
8
10
12
14
16
18
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07
Lo
g E
lect
rica
l R
esis
tivit
y,
(ohm
-cm
)
Total Filler Volume Fraction (CB+GNP)
47
experimental results in the statistical analysis. The formulations that make up the factorial
experiment are shown in Table 4-4.
Table 4-4: Weight Percent Filler in Factorial Design Formulations
Terms Ketjenblack EC-600 JD wt% TC307 wt%
(1) 0 0
A 0.33 0
B 0 5
AB 0.33 5
The factorial assessment was conducted on a Minitab version 17 Statistical
Software package. For all statistical calculations, the 95% confidence level was used. For
this analysis, the effects and P values for the log(ER) results were calculated. By taking
the logarithm of ER values, data can be easily compared in terms of orders of magnitude.
Small p values indicate that a factor, a filler, may have a significant effect on the log(ER)
result of the composite. The effects and P values are given in Table 4-5 for each filler
combination. The negative effect terms observed in the table demonstrate that composites
containing only single fillers cause a statistically significant decrease in electrical
resistivity.
Composites containing only carbon black have a larger effect term than the
composites that contained only graphene nanoplatelets. It is also noted that the
combinations of different fillers had a statistically significant effect on the log(ER) of the
composite. The negative effect of the interaction term means that adding 0.33 wt% CB
and 5 wt% GNP to epoxy caused the composite ER to be lower than what would be
48
expected from the additive effect of each single filler. The results suggest that the highly
branched CB and the GNP are likely forming electrically conductive networks. Fan et al.
also demonstrated that adding a small amount of CB decreased the ER of GNP/epoxy
composites [8].
Table 4-5: Factorial Design Analysis for the Logarithm of the Electrical Resistivity
(ohm-cm)
Terms Effect P
Constant - 0
5.0 wt% GNP -5.235 0
0.33 wt% CB -6.952 0
5.0 wt% GNP/0.33 wt% CB -5.022 0
4.3 Thermal Conductivity Results
4.3.1 Asbury Carbon’s TC307 GNP in Epoxy Thermal Conductivity Results
Table 4-6 shows the mean (with standard deviation) through-plane thermal
conductivity results of the studied composites as a function of filler volume and weight
fraction for the TC307 GNP composites. Compounding TC307 GNP in the epoxy matrix
doubled the thermal conductivity from ~0.2 W/m-K for the neat epoxy to ~0.4 W/m-K
for 20 wt% TC307 GNP epoxy composites. The resulting increase in thermal
conductivity could be useful in thermal dissipative applications. Adding more than 20
wt% TC307 GNP resulted in a material that was too viscous to fabricate samples from. It
has been reported by Wang et al. that adding 5 wt% XG Sciences GnP-C750 (GNP with
<1 μm average particle diameter, ~5 to 10 nm thickness, surface area ~750 𝑚2/g) to
EPON 828 epoxy resin with an m-phenylene diamine curing agent resulted in a slight
49
increase in thermal conductivity from ~0.22 to 0.24 W/m-K [9]. This is a result that is
consistent with the data reported in this study.
Table 4-6: Thermal Conductivity Results for TC307 GNP in Epoxy Composites
Formulation Filler Content
wt% (vol%)
Thermal Conductivity
(W/m-K) Count
Neat 0 (0) 0.206 ± 0.006 5
5% GNP 5.0 (3.1) 0.266 ± 0.002 5
10% GNP 10.0 (6.2) 0.304 ± 0.002 5
15% GNP 15.0 (9.6) 0.364 ± 0.008 4
20% GNP 20.0 (13.0) 0.394 ± 0.009 4
4.3.2 Akzo Nobel’s EC-600 JD CB in Epoxy Thermal Conductivity Results
Table 4-7 shows the mean (with standard deviation) through-plane thermal
conductivity results of the studied composites as a function of filler volume and weight
fraction for the Ketjenblack EC-600 JD CB composites. Compounding up to 1 wt%
Ketjenblack EC-600 JD CB in the epoxy matrix had no appreciable effect on the thermal
conductivity of the composite. The CB/epoxy composites had a thermal conductivity of
~0.2 W/m-K. Adding more than 1.0 wt% Ketjenblack EC-600 JD CB resulted in a
material that was too viscous to fabricate samples from due to the highly branched and
high surface area of the CB. An increase in composite thermal conductivity from ~0.2
W/m-K to ~0.4 W/m-K was observed by Abdel-Aal when adding 10 wt% of a lower
surface area CB to epoxy [5].
50
Table 4-7: Thermal Conductivity Results for Ketjenblack EC-600 JD CB in Epoxy
Composites
Formulation Filler Content
wt% (vol%)
Thermal Conductivity
(W/m-K) Count
Neat 0 (0) 0.206 ± 0.006 5
1/3% CB 0.33 (0.22) 0.212 ± 0.002 5
2/3% CB 0.67 (0.44) 0.216 ± 0.001 5
1% CB 1.0 (0.67) 0.210 ± 0.005 5
4.3.3 TC307 GNP and EC-600 JD CB in Epoxy Thermal Conductivity Results
Table 4-8 shows the mean (with standard deviation) through-plane thermal
conductivity results of the studied composites as a function of filler volume and weight
fraction for the TC307 GNP/Ketjenblack EC-600 JD CB composites. Compounding
TC307 GNP and Ketjenblack EC-600 JD CB in the epoxy matrix increased the thermal
conductivity from ~0.2 W/m-K for the neat epoxy to ~0.3 W/m-K for 0.33 wt%
Ketjenblack EC-600 JD CB and 10 wt% TC307 GNP in epoxy composites. The thermal
conductivity results of the 0.33 wt% CB and 5 wt% GNP in epoxy as well as the 0.33
wt% CB and 10 wt% GNP in epoxy were similar to that of the 5 wt% GNP in epoxy and
10 wt% GNP in epoxy composites, respectively.
51
Table 4-8: Thermal Conductivity Results for Ketjenblack EC-600 JD CB and TC307
GNP in Epoxy Composites
Formulation Filler Content
wt% (vol%)
Thermal Conductivity
(W/m-K) Count
Neat 0 0.206 ± 0.006 5
0.33 wt% CB 5 wt% GNP
CB: 0.33 (0.22) GNP: 5.0 (3.1) 0.265 ± 0.002 5
0.33 wt% CB 10 wt% GNP
CB: 0.33 (0.22) GNP: 10.0 (6.2) 0.304 ± 0.008 5
4.4 Tensile Results
4.4.1 Asbury Carbon’s TC307 GNP in Epoxy Tensile Results
Table 4-9 shows the mean (with standard deviation) ultimate tensile strength,
strain at ultimate tensile strength, and tensile modulus for the TC307 GNP in epoxy
composites measured according to ASTM D638. Adding GNP to the epoxy caused the
ultimate tensile strength to decrease from 77.6 MPa for the neat composites to 49.9 MPa
for the 20 wt% (13.0 vol%) TC307 GNP, shown in Figure 4-11. The strength remained
similar to that of the neat epoxy up to 10 wt% (6.3 vol%) GNP and then a steady decrease
in strength was observed for up to 20 wt% (13.0 vol%) GNP. The strain at ultimate
tensile strength decreased from 7.98% for the neat epoxy to 1.54% for the 20 wt% (13.0
vol%) TC307 GNP in epoxy composites, shown in Figure 4-12. The strain at ultimate
tensile strength decreased quickly with initial loading of TC307 GNP and decreased more
steadily with higher loadings. The tensile modulus steadily increased from 2.72 GPa for
the neat epoxy to 3.69 GPa for the composites containing 20 wt% (13.0 vol%) TC307
GNP in epoxy, shown in Figure 4-13. An increase in tensile modulus from ~2.7 GPa for
52
neat epoxy to 3.2 GPa for 5 wt% GnP-C750 in epoxy composites have been reported by
Wang et al. It was also observed that the tensile strength remained similar to that of the
neat resin [9]. Wang’s result was similar to what was observed in this study.
Table 4-9: Tensile Results for TC307 GNP in Epoxy Composites
Formulation Filler
Content wt% (vol%)
Tensile Modulus
(GPa)
Ultimate Tensile
Strength (Mpa)
Strain at Ultimate Tensile Strength
(%) Count
Neat 0 (0) 2.72 ± 0.04 77.6 ± 0.9 7.98 ± 0.35 6
5 wt% GNP 5.0 (3.1) 2.97 ± 0.07 72.9 ± 1.5 3.85 ± 0.12 7
10 wt% GNP 10.0 (6.2) 3.20 ± 0.11 70.0 ± 2.4 3.27 ± 0.27 5
15 wt% GNP 15.0 (9.6) 3.37 ± 0.04 61.8 ± 3.9 2.36 ± 0.23 5
20 wt% GNP 20.0 (13.0) 3.69 ± 0.08 49.9 ± 2.0 1.54 ± 0.08 5
Figure 4-11: Ultimate Tensile Strength Results for TC307 GNP in Epoxy
Composites
0
10
20
30
40
50
60
70
80
90
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14
Ult
imat
e T
ensi
le S
tren
gth
(M
Pa)
GNP Volume Fraction
53
Figure 4-12: Strain at Ultimate Strength Results for TC307 GNP in Epoxy Composites
Figure 4-13: Tensile Modulus Results for TC307 GNP in Epoxy Composites
4.4.2 Akzo Nobel’s EC-600 JD CB in Epoxy Tensile Results
Table 4-10 shows the mean (with standard deviation) ultimate tensile strength,
strain at ultimate tensile strength, and tensile modulus for the Ketjenblack EC-600 JD CB
0
1
2
3
4
5
6
7
8
9
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14
Str
ain a
t U
ltim
ate
Str
ength
(%
)
GNP Volume Fraction
2.5
2.7
2.9
3.1
3.3
3.5
3.7
3.9
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14
Ten
sile
Mo
dulu
s (G
Pa)
GNP Volume Fraction
54
in epoxy composites measured according to ASTM D638. Adding CB to the epoxy
resulted in a slight decrease in ultimate tensile strength from 77.6 MPa for neat epoxy to
80.4 MPa for 1.0 wt% Ketjenblack EC-600 JD CB composites, as shown in Figure 4-14.
A slight decrease in the strain at ultimate tensile strength was observed with the strain
from 8.0% for neat epoxy to 7.3% for 1.0 wt% Ketjenblack EC-600 JD CB composites,
as shown in Figure 4-15. Adding the CB resulted in no change in tensile modulus from
the neat epoxy. All CB composite formulations tested demonstrated an elastic modulus of
2.7 GPa, as shown in Figure 4-16. Abdel-Khalil et al. observed a decrease in tensile
strength from ~48 MPa for neat epoxy to ~38 MPa for 5 wt% carbon black made using
coconut shells in a diglycidyl ether of bisphenol A cured with an isophorone hardener.
They also reported a decrease in strain from ~4.4% for neat epoxy to 2.2% for 5 wt%
carbon black. In their study, the elastic modulus did not change with the addition of up to
5 wt% carbon black in epoxy [5].
Table 4-10: Tensile Results for Ketjenblack EC-600 JD in Epoxy Composites
Formulation Filler
Content wt% (vol%)
Tensile Modulus
(GPa)
Ultimate Tensile
Strength (Mpa)
Strain at Ultimate Tensile Strength
(%) Count
Neat 0 (0) 2.72 ± 0.04 77.6 ± 0.9 7.98 ± 0.35 6
0.33 wt% CB 0.33 (0.22) 2.72 ± 0.04 81.8 ± 0.4 7.28 ± 0.21 6
0.67 wt% CB 0.67 (0.44) 2.74 ± 0.04 81.5 ± 0.6 7.25 ± 0.38 5
1.0 wt% CB 1.0 (0.67) 2.74 ± 0.04 80.4 ± 0.4 7.34 ± 0.35 6
55
Figure 4-14: Ultimate Tensile Strength Results for Ketjenblack EC-600 JD CB in
Epoxy Composites
Figure 4-15: Strain at Ultimate Tensile Strength Results for Ketjenblack EC-600 JD
CB in Epoxy Composites
0
10
20
30
40
50
60
70
80
90
0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008
Ult
imat
e T
ensi
le S
tren
gth
(M
Pa)
CB Volume Fraction
0
1
2
3
4
5
6
7
8
9
0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008
Str
ain a
t U
ltim
ate
Str
ength
(%
)
CB Volume Fraction
56
Figure 4-16: Tensile Modulus Results for Ketjenblack EC-600 JD CB in Epoxy
Composites
4.4.3 TC307 GNP and EC-600 JD CB in Epoxy Tensile Results
Table 4-11 shows the mean (with standard deviation) ultimate tensile strength,
strain at ultimate tensile strength, and tensile modulus for the TC307 GNP and
Ketjenblack EC-600 JD CB in epoxy composites measured according to ASTM D638.
Figure 4-17 shows that adding TC307 GNP to the 0.33 wt% CB composite decreased the
ultimate strength of the composite from 81.8 MPa for the 0.33 wt% CB composite to 61.6
MPa for the 10 wt% GNP and 0.33 wt% CB composite. A decrease in strain at the
ultimate strength was observed in Figure 4-18 from 7.28% for the 0.33 wt% CB
composite to 2.45% for the 10 wt% GNP and 0.33 wt% CB composite. Figure 4-19
shows that the addition of TC307 GNP to the 0.33 wt% CB in epoxy composite increased
the tensile modulus from 2.72 GPa for the 0.33 wt% CB composite to 3.27 GPa for the 10
0
0.5
1
1.5
2
2.5
3
0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008
Ten
sile
Mo
dulu
s (G
Pa)
CB Volume Fraction
57
wt% GNP and 0.33 wt% GNP composites.
Table 4-11: Tensile Results for TC307 GNP and Ketjenblack EC-600 JD in Epoxy
Composites
Formulation Filler Content
wt% (vol%)
Tensile Modulus
(GPa)
Ultimate Tensile
Strength (Mpa)
Strain at Ultimate Tensile
Strength (%) Count
Neat 0 (0) 2.72 ± 0.04 77.6 ± 0.9 7.98 ± 0.35 6
0.33 wt% CB 5 wt% GNP
CB: 0.33 (0.22) GNP: 5.0 (3.1)
3.20 ± 0.08 68.3 ± 2.9 3.09 ± 0.27 5
1.0 wt% CB 10 wt% GNP
CB: 0.33 (0.22) GNP: 10.0 (6.2)
3.27 ± 0.10 61.6 ± 2.5 2.45 ± 0.20 6
Figure 4-17: Ultimate Tensile Strength Results for Ketjenblack EC-600 JD CB and
TC307 GNP in Epoxy Composites
0
10
20
30
40
50
60
70
80
90
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07
Ult
imat
e T
ensi
le S
tren
gth
(M
Pa)
Total Volume Fraction (CB+GNP)
58
Figure 4-18: Strain at Ultimate Tensile Strength Results for Ketjenblack EC-600 JD
CB and TC307 GNP in Epoxy Composites
Figure 4-17: Tensile Modulus Results for Ketjenblack EC-600 JD CB and TC307 GNP
in Epoxy Composites
0
1
2
3
4
5
6
7
8
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07
Str
ain a
t U
ltim
ate
Str
ength
(%
)
Total Volume Fraction (CB+GNP)
0
0.5
1
1.5
2
2.5
3
3.5
4
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07
Ten
sile
Mo
dulu
s (G
Pa)
Total Volume Fraction (CB+GNP)
59
The ultimate strength decreased when 0.33 wt% Ketjenblack EC-600 JD CB was
added to 5 wt% and 10 wt% TC307 in epoxy composites from 72.9 and 70.0 GPa for the
5 wt% and 10 wt% GNP composites to 68.3 and 61.6 GPa for the 5 wt% and 10 wt%
GNP composites with 0.33 wt% CB. The tensile modulus increased when adding 0.33
wt% Ketjenblack EC-600 JD CB to 5 wt% and 10 wt% TC307 in epoxy composites from
2.97 and 3.2 GPa for the 5 wt% and 10 wt% GNP composites to 3.20 and 3.27 for the 5
wt% and 10 wt% GNP composites with 0.33 wt% CB. The strain at ultimate strength
decreased when 0.33 wt% Ketjenblack EC-600 JD CB was added to 5 wt% and 10 wt%
TC307 in epoxy composites from 3.85% and 3.27% for the 5 wt% and 10 wt% GNP
composites to 3.09% to and 2.45% for the 5 wt% and 10 wt% GNP composites with 0.33
wt% CB.
4.4.4 Tensile Modulus Modeling
The experimental tensile modulus results of this study were compared to several different
models: Einstein’s, Guth and Smallwood’s, and Halpin-Tsai’s model. Einstein’s
equation, shown in Equation 4-1, predicts the elastic modulus of composite materials
using the volume fraction of the filler (𝑉𝑓) and the elastic modulus of the matrix (𝐸𝑚)
[10-12]. Einstein’s equation was originally developed for calculating incremental changes
in viscosity of suspensions with the inclusion of hard spheres. Later, an analogy had been
discovered between hydrodynamics of suspensions with rigid spheres and the
elastostatics of solids with the inclusion of rigid particles, allowing us to use this formula
as an approximation for the elastic modulus of an isotropic composite with small filler
loading levels.
60
𝐸𝐶 = 𝐸𝑚(1 + 2.5𝑉𝑓) [4-1]
Guth and Smallwood generalizes Einstein’s model for larger filler concentrations by
adding another term to the polynomial series expansion in order to account for
interparticle interactions as shown in Equation 4-2 [11][13][14].
𝐸𝐶 = 𝐸𝑚(1 + 2.5𝑉𝑓 + 14.1𝑉𝑓2) [4-2]
Halpin and Tsai developed a model that uses the fillers aspect ratio (L/t), shape factor (ξ),
volume fraction (𝑉𝑓) and elastic modulus (𝐸𝑓) as well as the elastic modulus of the matrix
(𝐸𝑚) to predict the modulus of the composite material (𝐸𝑐). The Halpin-Tsai model
predicts the tensile modulus of a composite with unidirectional and discontinuous fillers
by calculating theoretical longitudinal and transversal moduli of the composite using
Equation 4-3 and Equation 4-4. The parameters of 𝜂𝐿 and 𝜂𝑇 are calculated using
Equation 4-5 and Equation 4-6.
𝐸𝐿
𝐸𝑀=
1+ξ𝜂𝐿𝑉𝑓
1−𝜂𝐿𝑉𝑓 [4-3]
𝐸𝑇
𝐸𝑀=
1+2𝜂𝑇𝑉𝑓
1−𝜂𝑇𝑉𝑓 [4-4]
𝜂𝐿 =
𝐸𝑓
𝐸𝑀−1
𝐸𝑓
𝐸𝑀+ξ
[4-5]
𝜂𝑇 =
𝐸𝑓
𝐸𝑀−1
𝐸𝑓
𝐸𝑀+2
[4-6]
61
The composite tensile modulus for two-dimensional and three-dimensional (3D)
random orientation of fillers was calculated using Equation 4-7 and Equation 4-8. In this
study, the composites produced consist of 3D randomly oriented fillers [14-17].
𝐸𝐶 =3
8𝐸𝐿 +
5
8𝐸𝑇 [4-7]
𝐸𝐶 =1
5𝐸𝐿 +
4
5𝐸𝑇 [4-8]
Where 𝐸𝐶 is the composite tensile modulus. The tensile modulus of the matrix, 𝐸𝑀,
was experimentally determined to be 2.72 GPa and was used in these models. GNP
consists of multiple sheets stacked on one another. Though the tensile modulus of
graphene sheets are around 1000 GPa in the plane of the sheet, the van der Waal’s
dispersion bonding forces between sheets fail much sooner than the graphitic carbon-
carbon bonding within the sheets. The failure between sheets leads to further exfoliation
of the particle and so the modulus of exfoliation is used as the tensile modulus of the
filler for modeling purposes. Hence, the tensile modulus of the filler used in this model,
𝐸𝐹, is equal to 36.5 GPa [18]. For platelets, the filler shape factor, ξ, is equal to 0.667
(L/t) [19]. The filler aspect ratio, L/t, is 60 (mean platelet length = 750 nm and thickness
= 12.5 nm), which leads to a shape factor of 40.
Figure 4-18 shows the experimental tensile modulus data (mean with ±1 standard
deviation) for GNP/epoxy composites along with the predictions made by the Einstein,
Guth and Smallwood, and Halpin-Tsai 3D models. Microscopy performed on the
GNP/epoxy composites indicate that there is a 3D random orientation of GNP in the
62
epoxy matrix. Over the entire filler volume fraction range studied in this project, the
Einstein model gave the best prediction of composite tensile modulus.
Figure 4-20: Tensile Modulus of GNP/Epoxy Composites with Einstein, Guth-
Smallwood, and 3D Halpin-Tsai Models
4.5 References
[1] Wang Y, Yu J, Dai W, Song Y, Wang D, Zheng L, and Jiang N. “Enhanced thermal
and electrical properties of epoxy composites reinforced with graphene nanoplatelets”.
Polymer Composites (2016); 36: 556-565.
[2] Prolongo SG, Moriche R, Jimenez-Suarez A, Sanchez, M, and Urena A. “Advantages
and disadvantages of the addition of graphene nanoplatelets to epoxy resins”. European
Polymer Journal (2014); 61: 206-214.
[3] Chandrasekaran, S, Seidel, C, and Schulte K. “Preparation and characterization of
graphite nano-platelet (GNP)/epoxy nano-composite: mechanical, electrical, and thermal
properties”. European Polymer Journal (2013); 49: 3878-3888.
[4] Lu X, La P, Guo X, and Wei Y. “Study on microstructure and mechanical properties
of epoxy resin/carbon black composites prepared by in situ polymerization”. Applied
Mechanics and Materials (2012); 109: 156-160.
2.5
2.7
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.3
4.5
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14
Ten
sile
Mo
dulu
s (G
Pa)
GNP Volume Fraction
TC307 Tensile Modulus
TC307 Einstein Model
TC307 Guth/Smallwood Model
TC307 3D Halpin-Tsai Model
63
[5] Abdel-Aal N, El-Tantawy F, Al-Hajry A, and Boudoudina M. “Epoxy
resin/plasticized carbon black composites. Part 1. Electrical and thermal properties and
their applications”. Polymer Composites (2008); 29: 511-517.
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of carbon black and clay on the electrical and mechanical properties of epoxy
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Wiley, Inc., 2001.
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conductivity of graphene nanoplatelet/epoxy composite”. Material Science. 2015; 50:
1082-1093
[10] Einstein A. “Investigation on the Theory of the Brownian Movement”. Annals of
Physics. 1906: pp. 289-306.
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64
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65
5 Conclusions and Future Work
Conclusions were made about the composite types according to the results of tensile,
thermal and electrical conductivity tests. The conclusions were organized into a table as
shown in Table 5-1. The following sections describe the conclusions in more detail.
Table 5-1: A summary of the conclusions made about the composite types tested
Property
Carbon Black
Composites
(up to 1 wt%)
GNP Composites
(up to 20 wt%)
CB/GNP Composites
(0.33 wt% CB and up
to 10 wt% GNP)
ER
- Composites made
electrically
Conductive
- Percolation
threshold
at ~0.3 vol%
-Composites made
electrically
conductive
- Percolation
threshold
at ~12 wt%
(~7 vol%)
-Composites made
electrically
conductive
- Synergistic effect of
CB and GNP on ER
of composite
Tensile -Tensile properties
unchanged
- Mild decreases
in strength
- Large decreases
in strain
- Mild increases
in modulus
- Einstein's model best
- Mild decrease
in strength
- Large decrease
in strain
- Mild increases
in modulus
TC
-Thermal
conductivity
unchanged
-Thermal conductivity
doubled at 20 wt%
GNP composites
-GNP dominates
thermal conductivity
66
5.1 Electrical Resistivity Properties for Neat Epoxy, GNP/Epoxy, CB/Epoxy, and GNP/CB/Epoxy Composites
Electrical resistivity (ER) tests were conducted for neat epoxy, GNP/epoxy,
CB/epoxy, and GNP/CB/epoxy composites. The data was used to determine the
percolation threshold of the carbon single filler epoxy composites (GNP/epoxy and
CB/epoxy) and to determine if there were synergistic effects between CB and GNP filler
concentrations by conducting a factorial design on the composite ER. The ER of the neat
epoxy is 2.88 × 1016 Ω-cm. Adding up to 20 wt% GNP to the neat epoxy decreased the
ER to 6.05 × 105 Ω-cm. The percolation threshold for the GNP/epoxy composites was
observed to be at ~7 vol% (12 wt%) GNP. Adding up to 1 wt% CB to the neat epoxy
decreased the ER to 756 Ω-cm. The percolation threshold for the CB/epoxy composites
was determined to be 0.3 vol% Ketjenblack EC-600 JD CB. Adding 1/3 wt% CB to up to
10 wt% GNP decreased the ER from 9.41 × 1015 Ω-cm for the 10 wt% GNP in epoxy
formulation to 6,400 Ω-cm for the 0.33 wt% CB/10 wt% GNP/epoxy composite.
The 0.33 wt% Ketjenblack EC-600 JD CB/epoxy composite and the 5 and 10 wt%
TC307 GNP/epoxy composites could be used for electrically insulating applications,
including Polymer Core Composite Conductors to be used in power transmission lines.
The 0.67 and 1.0 wt% CB in epoxy composites and both of the combination composites
(0.33 wt% CB with 5 wt% GNP and 0.33 wt% CB with 10 wt% GNP) could be used for
semi-conductive applications. The 15 wt% GNP and 20 wt% GNP in epoxy composites
could be used for static dissipative applications. These results are organized in Table 5-1.
67
Table 5-2: Potential applications for composite formulations tested for ER
Application Formulation ER (Ω-cm)
Electrically Insulating Applications
( > 1011Ω-cm)
-PCCC transmission lines
0.33 wt% CB/epoxy 2.50 x 10^14
5 wt% GNP/epoxy 1.40 x 10^16
10 wt% GNP/epoxy 9.41 x 10^15
Static Dissipative Applications
(~105 to 1010Ω-cm)
-Sensitive electronics
15 wt% GNP/epoxy 7.42 x 10^6
20 wt% GNP/epoxy 6.05 x 10^5
Semi-conductive Applications
(~10 to 104 Ω-cm)
-Aerospace
0.67 wt% CB/epoxy 6,440
1.0 wt% CB/epoxy 756
0.33 wt% CB/5 wt%
GNP/epoxy 15,600
0.33 wt% CB/10 wt%
GNP/epoxy 6,400
The factorial design on the GNP and CB concluded that at the 95% confidence
level, the combination of adding 5 wt% GNP and 0.33 wt% CB to an epoxy composite
caused the ER to decrease by a statistically significant amount. The ER decreased more
than what would be expected from the additive effect of each independent filler in epoxy
by itself. The results suggest that the highly branched CB and the GNP are likely forming
electrically conductive networks. Per the authors’ knowledge, electrical conductivity
properties for these loading levels of Asbury Carbons TC307 GNP and Ketjenblack EC-
600 JD in this epoxy system (EPON 862 with EPIKURE Curing Agent W) have not been
previously reported in the open literature.
68
5.2 Thermal Conductivity Properties for Neat Epoxy, GNP/Epoxy, CB/Epoxy, and GNP/CB/Epoxy Composites
Adding 20 wt% GNP to epoxy caused the composite thermal conductivity to
double from ~0.2𝑊
𝑚∙𝐾 to ~0.4
𝑊
𝑚∙𝐾. Adding up to 1 wt% CB in epoxy did not appreciably
change the thermal conductivity of the neat epoxy which remained at about ~0.2𝑊
𝑚∙𝐾.
The thermal conductivity of the CB/GNP/epoxy composites were similar to the thermal
conductivities of the similar loading of GNP/epoxy composites. Higher thermal
conductivities could help dissipate heat in high temperature and voltage applications such
as in PCCC technology. Per the authors’ knowledge, thermal conductivity properties for
these loading levels of Asbury Carbons TC307 GNP and Ketjenblack EC-600 JD in this
epoxy system (EPON 862 with EPIKURE Curing Agent W) have not been previously
reported in the open literature.
5.3 Tensile Properties for Neat Epoxy, GNP/Epoxy, CB/Epoxy, and GNP/CB/Epoxy Composites
For the GNP/epoxy composites (5, 10, 15 and 20 wt% GNP), the ultimate tensile
strength did not change much from the neat epoxy for the 5 and 10 wt% TC307 GNP in
epoxy composites (~70 MPa) and decreased to 49.9 MPa at 20 wt% TC307 GNP in
epoxy composites. The strain at the ultimate tensile strength decreased immediately for
epoxy composites after compounding with GNP from 8.0% for neat epoxy to 1.5% for 20
wt% TC307 GNP. The GNP/epoxy composites showed steady increases in elastic
modulus from 2.72 GPa for neat epoxy to 3.69 GPa for the 20 wt% TC307 GNP in epoxy
69
composites. The tensile results for the 5 and 10 wt% GNP in epoxy are encouraging
because they can be used in Polymer Core Composite Conductors in power transmission
lines, where the increased elastic modulus and thermal conductivity (useful to dissipate
heat) are needed along with good strength (~70 MPa) and acceptable strain (≥ 3.3%).
The Einstein model for the elastic modulus was the model that predicted the tensile
modulus best.
For the CB/epoxy composites (0.33, 0.67, and 1.0 wt% CB), the strength, strain,
and modulus remained relatively constant at ~80 MPa, ~7.3%, and 2.7 MPa, respectively.
This result is exciting because the ER of the 0.67 and 1.0 wt% CB/epoxy was
significantly reduced without degradation of the tensile properties. Per the authors’
knowledge, tensile properties for these loading levels of Asbury Carbons TC307 GNP
and Ketjenblack EC-600 JD in this epoxy system (EPON 862 with EPIKURE Curing
Agent W) have not been previously reported in the open literature.
The combination filler composites experienced decreases in ultimate strength and
strain and increases in elastic modulus when adding 0.33 wt% CB to 5 and 10 wt%
GNP/epoxy composites. Adding 0.33 wt% CB to the TC307 GNP composites decreased
the ultimate strength of the composite from 70 MPa for the 10 wt% GNP composites to
61.6 MPa for the 10 wt% GNP and 0.33 wt% CB composite. A decrease in strain at the
ultimate strength was observed from 3.3% for the 10 wt% GNP composites to 2.45% for
the 10 wt% GNP and 0.33 wt% CB composite. The addition of 0.33 wt% CB to TC307
GNP in epoxy composites increased the tensile modulus from 3.2 GPa for the 10 wt%
GNP composite to 3.3 GPa for the 10 wt% GNP and 0.33 wt% GNP composites. The
70
author could not find published papers in the open literature that reported the tensile
properties of similar loading levels of combinations of TC307 GNP and EC-600 JD CB
in epoxy.
5.4 Recommendations for Future Work
This project demonstrated that adding GNP to an epoxy matrix will increase the
elastic modulus of the composite. There are many types of GNP with a variety of sizes
that can be compounded into an epoxy matrix to be characterized. This project also
demonstrated that adding CB to an epoxy will increase the electrical conductivity of the
composite. Other conductive carbon blacks are available that can be compounded into a
epoxy matrix to be characterized. It could also be beneficial to experiment with higher
filler volume fractions as well as different combinations of the TC307 GNP and
Ketjenblack EC-600 JD CB in order to characterize the tensile properties as well as the
thermal and electrical conductivities.
Other tests can be done to further characterize the composite materials fabricated in
this study. The conductive composite materials to be used in high voltage applications
and with an ER between 101 − 104 Ω-cm can be tested for the glass transition
temperature and the insulating composite materials can be tested for the dielectric
constant. An aging study could be done on the conductive composite materials as well to
determine how the properties change after the material has undergone simulated aging
71
processes similar to that which would be experienced by high voltage transmission lines
in real world conditions.
72
A Appendix A: Electrical Resistivity Results
Table A-1: ASTM D257 Through-Plane Electrical Resistivity Results for Neat Epoxy
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
A862-4-17-12-1 100 2.8174E+16
A862-4-17-12-2 100 3.1263E+16
A862-4-17-12-3 100 2.8694E+16
A862-4-17-12-4 100 3.3570E+16
A862-4-17-12-5 100 2.5305E+16
A862-4-17-12-6 100 2.5670E+16
Average 2.8779E+16
Standard Deviation 3.2010E+15
Count 6
Table A-2: ASTM D257 Through-Plane Electrical Resistivity Replicate Results for
Neat Epoxy
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-6-22-17-1 100 1.8415E+16
U862-W-6-22-17-2 100 1.8105E+16
U862-W-6-22-17-3 100 1.8485E+16
U862-W-6-22-17-4 100 1.8457E+16
U862-W-6-22-17-5 100 1.9001E+16
U862-W-6-22-17-6 100 1.8404E+16
Average 1.8478E+16
Standard Deviation 2.9072E+14
Count 6
73
Table A-3: ASTM D257 Through-Plane Electrical Resistivity Results for 5 wt% TC307
GNP in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-5T-6-23-17-1 100 1.2495E+16
U862-W-5T-6-23-17-2 100 1.4459E+16
U862-W-5T-6-23-17-3 100 1.3771E+16
U862-W-5T-6-23-17-4 100 1.4868E+16
U862-W-5T-6-23-17-5 100 1.4472E+16
Average 1.4013E+16
Standard Deviation 9.3588E+14
Count 5
Table A-4: ASTM D257 Through-Plane Electrical Resistivity Replicate Results for 5
wt% TC307 GNP in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-5T-11-2-17-1 100 1.4008E+16
U862-W-5T-11-2-17-2 100 1.2254E+16
U862-W-5T-11-2-17-3 100 1.4985E+16
U862-W-5T-11-2-17-4 100 1.6758E+16
U862-W-5T-11-2-17-5 100 1.3006E+16
Average 1.4202E+16
Standard Deviation 1.7613E+15
Count 5
74
Table A-5: ASTM D257 Through-Plane Electrical Resistivity Results for 10 wt%
TC307 GNP in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-10T-6-26-17-1 100 8.4584E+15
U862-W-10T-6-26-17-2 100 1.0553E+16
U862-W-10T-6-26-17-3 100 9.3155E+15
U862-W-10T-6-26-17-4 100 9.3646E+15
U862-W-10T-6-26-17-5 100 9.3627E+15
Average 9.4108E+15
Standard Deviation 7.4586E+14
Count 5
Table A-6: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for 15 wt%
TC307 GNP in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-15T-6-29-17-16 10 1.7635E+06
U862-W-15T-6-29-17-19 10 7.1472E+06
U862-W-15T-6-29-17-20 10 6.3793E+06
U862-W-15T-6-29-17-22 10 1.0233E+07
U862-W-15T-6-29-17-23 10 8.8090E+06
U862-W-15T-6-29-17-24 10 1.3061E+07
U862-W-15T-6-29-17-25 10 4.5661E+06
Average 7.4228E+06
Standard Deviation 3.7186E+06
Count 7
75
Table A-7: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for 20 wt%
TC307 GNP in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-20T-7-12-17-7 10 5.8562E+05
U862-W-20T-7-12-17-8 10 5.0352E+05
U862-W-20T-7-12-17-9 10 6.2961E+05
U862-W-20T-7-12-17-10 10 4.8639E+05
U862-W-20T-7-12-17-2 10 8.2087E+05
Average 6.0520E+05
Standard Deviation 1.3412E+05
Count 5
Table A-8: ASTM D257 Through-Plane Electrical Resistivity Results for 0.33%
Ketjenblack EC-600 JD CB in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-0.33A-8-15-17-1 10 2.8039E+14
U862-W-0.33A-8-15-17-2 10 3.5058E+14
U862-W-0.33A-8-15-17-3 10 3.9075E+14
U862-W-0.33A-8-15-17-4 10 1.1813E+14
U862-W-0.33A-8-15-17-5 10 1.1196E+14
Average 2.5036E+14
Standard Deviation 1.2971E+14
Count 5
76
Table A-9: ASTM D257 Through-Plane Electrical Resistivity Replicate Results for
0.33% Ketjenblack EC-600 JD CB in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-0.33A-11-1-17-1 10 1.4651E+14
U862-W-0.33A-11-1-17-2 10 2.4172E+14
U862-W-0.33A-11-1-17-3 10 4.2299E+14
U862-W-0.33A-11-1-17-4 10 2.1244E+14
U862-W-0.33A-11-1-17-5 10 4.4208E+14
Average 2.9315E+14
Standard Deviation 1.3200E+14
Count 5
Table A-10: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for 0.67%
Ketjenblack EC-600 JD CB in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-0.67A-8-14-17-6 0.5 4.4278E+03
U862-W-0.67A-8-14-17-6a 0.5 6.9152E+03
U862-W-0.67A-8-14-17-7 0.5 9.1601E+03
U862-W-0.67A-8-14-17-7a 0.5 5.5546E+03
U862-W-0.67A-8-14-17-17 0.5 5.8028E+03
U862-W-0.67A-8-14-17-17a 0.5 6.7857E+03
Average 6.4411E+03
Standard Deviation 1.6114E+03
Count 6
77
Table A-11: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for 1 wt%
Ketjenblack EC-600 JD CB in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-1A-8-3-17-1a 0.1 7.3775E+02
U862-W-1A-8-3-17-1 0.1 8.2728E+02
U862-W-1A-8-3-17-8 0.1 7.5528E+02
U862-W-1A-8-3-17-8a 0.1 8.0832E+02
U862-W-1A-8-3-17-21 0.1 7.2331E+02
U862-W-1A-8-3-17-21a 0.1 6.8150E+02
Average 7.5557E+02
Standard Deviation 5.4350E+01
Count 6
Table A-12: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for 0.33
wt% Ketjenblack EC-600 JD CB and 5 wt% TC307 GNP in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-0.33A-5T-8-28-17-17 2.5 1.5477E+04
U862-W-0.33A-5T-8-28-17-17a 2.5 1.4590E+04
U862-W-0.33A-5T-8-28-17-23 2.5 1.6970E+04
U862-W-0.33A-5T-8-28-17-16 2.5 1.3889E+04
U862-W-0.33A-5T-8-28-17-16a 2.5 1.3934E+04
U862-W-0.33A-5T-8-28-17-18 2.5 1.8582E+04
Average 1.5574E+04
Standard Deviation 1.8710E+03
Count 6
78
Table A-13: ASTM D4496 Two Point In-Plane Electrical Resistivity Replicate Results
for 0.33 wt% Ketjenblack EC-600 JD CB and 5 wt% TC307 GNP in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-0.33A-5T-8-28-17-18a 2.5 1.5646E+04
U862-W-0.33A-5T-8-28-17-20a 2.5 1.3100E+04
U862-W-0.33A-5T-8-28-17-21 2.5 1.4829E+04
U862-W-0.33A-5T-8-22-17-18 2.5 1.8349E+04
U862-W-0.33A-5T-8-22-17-21a 2.5 1.3369E+04
U862-W-0.33A-5T-8-22-17-19 2.5 1.1459E+04
Average 1.4459E+04
Standard Deviation 2.3964E+03
Count 6
Table A-14: ASTM D4496 Two Point In-Plane Electrical Resistivity Results for 0.33
wt% Ketjenblack EC-600 JD CB and 10 wt% TC307 GNP in Epoxy Composites
Sample Number
Applied Voltage
(V) Volume Electrical Resistivity (Ω-cm)
U862-W-0.33A-10T-8-24-17-20 5 4.7260E+03
U862-W-0.33A-10T-8-24-17-21 5 7.9261E+03
U862-W-0.33A-10T-8-24-17-22 5 4.7698E+03
U862-W-0.33A-10T-8-24-17-23 5 5.7482E+03
U862-W-0.33A-10T-8-30-17-18a 5 8.8384E+03
Average 6.4017E+03
Standard Deviation 1.8815E+03
Count 5
79
B Appendix B: Thermal Conductivity Results at 55°C
Table B-1: Thermal Conductivity of Neat Epoxy
Test Date Sample Number Through Plane Thermal Conductivity (W/m•K)
7/28/2017 862W4-17-12-1 0.1980
7/28/2017 862W4-17-12-3 0.2091
7/28/2017 862W4-17-12-4 0.2096
8/2/2017 862W4-17-12-5 0.2113
8/2/2017 862W4-17-12-6 0.2000
Average 0.2056
Standard Deviation 0.0061
Number of Samples 5
Table B-2: Thermal Conductivity of 5 wt% TC307 GNP in Epoxy Composites
Test Date Sample Number Through Plane Thermal Conductivity (W/m•K)
7/24/2017 862W-5T-6-23-17-1 0.2691
7/24/2017 862W-5T-6-23-17-2 0.2652
7/24/2017 862W-5T-6-23-17-3 0.2649
7/24/2017 862W-5T-6-23-17-4 0.2655
7/24/2017 862W-5T-6-23-17-5 0.2649
Average 0.2659
Standard Deviation 0.0018
Number of Samples 5
80
Table B-3: Thermal Conductivity of 10 wt% TC307 GNP in Epoxy Composites
Test Date Sample Number Through Plane Thermal Conductivity (W/m•K)
7/24/2017 862W-10T-6-23-17-1 0.3011
7/24/2017 862W-10T-6-23-17-2 0.3033
7/24/2017 862W-10T-6-23-17-3 0.3033
7/24/2017 862W-10T-6-23-17-4 0.3055
7/24/2017 862W-10T-6-23-17-5 0.3048
Average 0.3036
Standard Deviation 0.0017
Number of Samples 5
Table B-4: Thermal Conductivity of 15 wt% TC307 GNP in Epoxy Composites
Test Date Sample Number Through Plane Thermal Conductivity (W/m•K)
8/14/2017 862W-15T-2 0.3598
8/14/2017 862W-15T-3 0.3630
8/14/2017 862W-15T-4 0.3751
8/14/2017 862W-15T-5 0.3583
Average 0.3641
Standard Deviation 0.0076
Number of Samples 4
Table B-5: Thermal Conductivity of 20 wt% TC307 GNP in Epoxy Composites
Test Date Sample Number Through Plane Thermal Conductivity (W/m•K)
8/16/2017 862W-20T-1 0.3900
8/16/2017 862W-20T-2 0.3998
8/16/2017 862W-20T-3 0.4020
8/16/2017 862W-20T-4 0.3830
Average 0.3937
Standard Deviation 0.0088
Number of Samples 4
81
Table B-6: Thermal Conductivity of 0.33 wt% Ketjenblack EC-600 JD CB in Epoxy
Composites
Test Date Sample Number Through Plane Thermal Conductivity (W/m•K)
9/6/2017 862W-0.33A-1 0.2117
9/6/2017 862W-0.33A-2 0.2115
9/6/2017 862W-0.33A-3 0.2107
9/6/2017 862W-0.33A-4 0.2097
9/6/2017 862W-0.33A-5 0.2137
Average 0.2115
Standard Deviation 0.0015
Number of Samples 5
Table B-7: Thermal Conductivity of 0.67 wt% Ketjenblack EC-600 JD CB in Epoxy
Composites
Test Date Sample Number Through Plane Thermal Conductivity (W/m•K)
9/11/2017 862W-0.67A-1 0.2151
9/11/2017 862W-0.67A-2 0.2167
9/11/2017 862W-0.67A-3 0.2148
9/11/2017 862W-0.67A-4 0.2157
9/11/2017 862W-0.67A-5 0.2167
Average 0.2158
Standard Deviation 0.0009
Number of Samples 5
Table B-8: Thermal Conductivity of 1 wt% Ketjenblack EC-600 JD CB in Epoxy
Composites
Test Date Sample Number Through Plane Thermal Conductivity (W/m•K)
9/11/2017 862W-1A-1 0.2063
9/11/2017 862W-1A-2 0.2103
9/11/2017 862W-1A-3 0.2139
9/11/2017 862W-1A-4 0.2154
9/11/2017 862W-1A-5 0.2043
Average 0.2100
Standard Deviation 0.0048
Number of Samples 5
82
Table B-9: Thermal Conductivity of 0.33 wt% Ketjenblack EC-600 JD CB and 5 wt%
TC307 GNP in Epoxy Composites
Test Date Sample Number Through Plane Thermal Conductivity (W/m•K)
9/13/2017 862W-0.33A5T-1 0.2666
9/13/2017 862W-0.33A5T-2 0.2646
9/13/2017 862W-0.33A5T-3 0.2671
9/13/2017 862W-0.33A5T-4 0.2632
9/13/2017 862W-0.33A5T-5 0.2614
Average 0.2646
Standard Deviation 0.0024
Number of Samples 5
Table B-10: Thermal Conductivity of 0.33 wt% Ketjenblack EC-600 JD CB and 10 wt%
TC307 GNP in Epoxy Composites
Test Date Sample Number Through Plane Thermal Conductivity (W/m•K)
9/18/2017 862W-0.33A10T-1 0.3091
9/18/2017 862W-0.33A10T-2 0.3068
9/18/2017 862W-0.33A10T-3 0.2982
9/18/2017 862W-0.33A10T-4 0.3115
9/18/2017 862W-0.33A10T-5 0.2925
Average 0.3036
Standard Deviation 0.0080
Number of Samples 5
83
C Appendix C: Tensile Results
Figure C-1: Tensile Results for Neat Epoxy
Table C-1: Tensile Results for Neat Epoxy
Sample No.
Ultimate Tensile Stress (Mpa)
Strain at Ultimate Tensile Stress
(%)
Tensile Fracture Stress (MPa)
Strain at Tensile Fracture Stress
(%)
Tensile Modulus
(GPa)
A862-12-6-11 3 76.998 8.013 76.986 8.189 2.717
A862-4-17-12 3 77.854 8.18 75.559 12.209 2.757
A862-4-17-12 4 78.9 7.898 77.279 10.858 2.782
A862-4-17-12 7 76.976 8.272 74.873 11.852 2.71
A862-4-17-12 10 76.591 8.201 74.569 11.701 2.691
A862-4-17-12 12 78.065 7.335 78.065 7.335 2.678
Average 77.56 7.98 76.22 10.36 2.72
Standard Deviation 0.86 0.35 1.42 2.08 0.04
Count 6 6 6 6 6
0
10
20
30
40
50
60
70
80
90
0 0.05 0.1 0.15
Str
ess (
MP
a)
Strain (mm/mm)
Neat Epoxy
A862-12-6-11(3)
A862-4-17-13(3)
A862-4-17-12(4)
A862-4-17-12(7)
A862-4-17-12(10)
A862-4-17-12(12)
84
Figure C-2: Tensile Results for 5 wt% TC307 GNP in Epoxy Composites
Table C-2: Tensile Results for 5 wt% TC307 GNP in Epoxy Composites
Specimen
Ultimate Tensile Stress (MPa)
Strain at Ultimate Tensile Stress
(%)
Tensile Fracture Stress (Mpa)
Strain at Tensile Fracture Stress
(%)
Tensile Modulus
(GPa)
U862-W-5T-6-23-17-1 72.561 3.799 72.561 3.799 2.917
U862-W-5T-6-23-17-2 75.816 3.991 75.816 3.991 3.061
U862-W-5T-6-23-17-3 73.597 3.829 73.597 3.829 3.044
U862-W-5T-6-23-17-5 71.561 3.68 71.561 3.68 2.911
U862-W-5T-6-23-17-6 73.127 3.789 73.127 3.789 3.036
U862-W-5T-6-23-17-9 72.191 3.835 72.191 3.835 2.91
U862-W-5T-6-23-17-11 71.672 4.03 71.672 4.03 2.927
Average 72.93 3.85 72.93 3.85 2.97
Std Dev 1.47 0.12 1.47 0.12 0.07
Count 7 7 7 7 7
0
10
20
30
40
50
60
70
80
0 0.01 0.02 0.03 0.04 0.05
Str
ess (
MP
a)
Strain (mm/mm)
U862-W-5T-6-23-17
1
2
3
5
6
9
11
85
Figure C-3: Tensile Results for 10 wt% TC307 GNP in Epoxy Composites
Table C-3: Tensile Results for 10 wt% TC307 GNP in Epoxy Composites
Specimen
Ultimate Tensile Stress (MPa)
Strain at Ultimate Tensile Stress
(%)
Tensile Fracture Stress (Mpa)
Strain at Tensile Fracture Stress
(%)
Tensile Modulus
(GPa)
U862-W-10T-6-28-17-1 73.633 3.621 73.633 3.621 3.073
U862-W-10T-6-28-17-9 69.704 3.239 69.704 3.239 3.179
U862-W-10T-6-28-17-11 68.154 2.98 68.154 2.98 3.362
U862-W-10T-6-28-17-12 71.074 3.47 71.074 3.47 3.24
U862-W-10T-6-28-17-13 67.601 3.06 67.601 3.06 3.125
Average 70.03 3.27 70.03 3.27 3.2
Std Dev 2.43 0.27 2.43 0.27 0.11
Count 5 5 5 5 5
0
10
20
30
40
50
60
70
80
0 0.01 0.02 0.03 0.04
Str
ess (
MP
a)
Strain (mm/mm)
U862-W-10T-6-28-17
1
9
11
12
13
86
Figure C-4: Tensile Results for 15 wt% TC307 GNP in Epoxy Composites
Table C-4: Tensile Results for 15 wt% TC307 GNP in Epoxy Composites
Specimen
Ultimate Tensile Stress (MPa)
Strain at Ultimate Tensile Stress
(%)
Tensile Fracture Stress (Mpa)
Strain at Tensile Fracture Stress
(%)
Tensile Modulus
(GPa)
U862-W-15T-6-29-17-2 59.123 2.2 59.123 2.2 3.352
U862-W-15T-6-29-17-10 65.675 2.52 65.675 2.52 3.429
U862-W-15T-6-29-17-11 56.559 2.049 56.559 2.049 3.377
U862-W-15T-6-29-17-13 64.639 2.57 64.639 2.57 3.379
U862-W-15T-6-29-17-14 63.227 2.48 63.227 2.48 3.331
Average 61.84 2.36 61.84 2.36 3.37
Std Dev 3.86 0.23 3.86 0.23 0.06
Count 5 5 5 5 5
0
10
20
30
40
50
60
70
0 0.005 0.01 0.015 0.02 0.025 0.03
Str
ess (
MP
a)
Strain (mm/mm)
U862-W-15T-6-29-17
2
10
11
13
14
87
Figure C-5: Tensile Results for 20 wt% TC307 GNP in Epoxy Composites
Table C-5: Tensile Results for 20 wt% TC307 GNP in Epoxy Composites
Specimen
Ultimate Tensile Stress (MPa)
Strain at Ultimate Tensile Stress
(%)
Tensile Fracture Stress (Mpa)
Strain at Tensile Fracture Stress
(%)
Tensile Modulus
(GPa)
U862-W-20T-7-12-17-5 52.887 1.66 52.887 1.66 3.706
U862-W-20T-7-12-17-6 49.785 1.51 49.785 1.51 3.775
U862-W-20T-7-12-17-7 48.39 1.53 48.39 1.53 3.57
U862-W-20T-7-12-17-9 50.276 1.56 50.276 1.56 3.667
U862-W-20T-7-12-17-10 47.911 1.44 47.911 1.44 3.728
Average 49.85 1.54 49.85 1.54 3.69
Std Dev 1.96 0.08 1.96 0.08 0.08
Count 5 5 5 5 5
0
10
20
30
40
50
60
0 0.005 0.01 0.015 0.02
Str
ess (
MP
a)
Strain (mm/mm)
U862-W-20T-7-12-17
5
6
7
9
10
88
Figure C-6: Tensile Results for 0.33 wt% EC-600 JD in Epoxy Composites
Table C-6: Tensile Results for 0.33 wt% Ketjenblack EC-600 JD CB in Epoxy
Composites
Specimen
Ultimate Tensile Stress (MPa)
Strain at Ultimate Tensile
Stress (%)
Tensile Fracture Stress (MPa)
Strain at Tensile Fracture
Stress (%)
Tensile Modulus
(GPa)
U862-W-0.33A-8-21-17-12 81.360 7.431 81.360 7.431 2.738
U862-W-0.33A-8-21-17-14 82.100 7.340 81.599 8.471 2.753
U862-W-0.33A-8-21-17-15 81.940 6.920 81.900 7.411 2.760
U862-W-0.33A-8-21-17-16 81.610 7.361 81.320 8.519 2.724
U862-W-0.33A-8-21-17-20 81.470 7.150 80.630 8.450 2.669
U862-W-0.33A-8-21-17-22 82.240 7.489 82.200 7.960 2.691
Average 81.79 7.28 81.50 8.04 2.72
Std Dev 0.36 0.21 0.54 0.52 0.04
Count 6 6 6 6 6
0
10
20
30
40
50
60
70
80
90
0 0.02 0.04 0.06 0.08 0.1
Str
ess (
MP
a)
Strain (mm/mm)
U862-W-0.33A-8-21-17
12
14
15
16
20
22
89
Figure C-7: Tensile Results for 0.67 wt% Ketjenblack EC-600 JD in Epoxy Composites
Table C-7: Tensile Results for 0.67 wt% Ketjenblack EC-600 JD in Epoxy Composites
Specimen
Ultimate Tensile Stress (MPa)
Strain at Ultimate Tensile
Stress (%)
Tensile Fracture Stress (MPa)
Strain at Tensile Fracture
Stress (%)
Tensile Modulus
(GPa)
U862-W-0.67A-8-14-17-1 82.190 7.600 81.911 8.140 2.696
U862-W-0.67A-8-14-17-11 80.890 7.281 80.890 7.281 2.735
U862-W-0.67A-8-14-17-16 81.390 7.570 81.000 8.390 2.719
U862-W-0.67A-8-14-17-18 81.930 6.661 81.930 6.661 2.789
U862-W-0.67A-8-14-17-20 80.940 7.151 80.829 7.640 2.766
Average 81.47 7.25 81.31 7.62 2.74
Std Dev 0.58 0.38 0.56 0.69 0.04
Count 5 5 5 5 5
0
10
20
30
40
50
60
70
80
90
0 0.02 0.04 0.06 0.08 0.1
Str
ess (
MP
a)
Strain (mm/mm)
U862-W-0.67A-8-14-17
1
11
16
18
20
90
Figure C-8: Tensile Results for 1 wt% Ketjenblack EC-600 JD in Epoxy Composites
Table C-8: Tensile Results for 1 wt% Ketjenblack EC-600 JD in Epoxy Composites
Specimen
Ultimate Tensile Stress (MPa)
Strain at Ultimate Tensile
Stress (%)
Tensile Fracture Stress (MPa)
Strain at Tensile Fracture
Stress (%)
Tensile Modulus
(GPa)
U862-W-1A-8-3-17-2 80.131 7.310 80.131 7.310 2.712
U862-W-1A-8-3-17-5 80.660 7.311 80.660 7.311 2.714
U862-W-1A-8-3-17-7 80.510 7.331 80.510 7.331 2.749
U862-W-1A-8-3-17-13 79.870 7.719 79.870 7.719 2.699
U862-W-1A-8-3-17-14 80.312 6.731 80.312 6.731 2.798
U862-W-1A-8-3-17-15 80.820 7.660 80.820 7.660 2.742
Average 80.38 7.34 80.38 7.34 2.74
Std Dev 0.35 0.35 0.35 0.35 0.04
Count 6 6 6 6 6
0
10
20
30
40
50
60
70
80
90
0 0.02 0.04 0.06 0.08 0.1
Str
ess (
MP
a)
Strain (mm/mm)
U862-W-1A-8-3-17
2
5
7
13
14
15
91
Figure C-9: Tensile Results for 0.33 wt% Ketjenblack EC-600 JD CB and 5 wt%
TC307 GNP in Epoxy Composites
Table C-9: Tensile Results for 0.33 wt% Ketjenblack EC-600 JD CB and 5 wt% TC307
GNP in Epoxy Composites
Specimen
Ultimate Tensile Stress (MPa)
Strain at Ultimate Tensile Stress
(%)
Tensile Fracture Stress (Mpa)
Strain at Tensile Fracture Stress
(%)
Tensile Modulus
(GPa)
U862-W-0.33A-5T-8-28-17-2 66.115 2.879 66.115 2.879 3.3
U862-W-0.33A-5T-8-28-17-3 65.309 2.8 65.309 2.8 3.151
U862-W-0.33A-5T-8-28-17-4 71.905 3.44 71.905 3.44 3.252
U862-W-0.33A-5T-8-28-17-6 70.791 3.3 70.791 3.3 3.112
U862-W-0.33A-5T-8-28-17-7 67.292 3.039 67.292 3.039 3.176
Average 68.28 3.09 68.28 3.09 3.2
Std Dev 2.91 0.27 2.91 0.27 0.08
Count 5 5 5 5 5
0
10
20
30
40
50
60
70
80
0 0.01 0.02 0.03 0.04
Str
ess (
MP
a)
Strain (mm/mm)
U862-W-0.33A-5T-8-28-17
2
3
4
6
7
92
Figure C-10: Tensile Results for 0.33 wt% Ketjenblack EC-600 JD CB and 10 wt%
TC307 GNP in Epoxy Composites
Table C-10: Tensile Results for 0.33 wt% Ketjenblack EC-600 JD CB and 10 wt%
TC307 GNP in Epoxy Composites
Specimen
Ultimate Tensile Stress (MPa)
Strain at Ultimate Tensile Stress
(%)
Tensile Fracture Stress (Mpa)
Strain at Tensile Fracture Stress
(%)
Tensile Modulus
(GPa)
U862-W-0.33A-10T-8-30-17-2 60.324 2.36 60.324 2.36 3.282
U862-W-0.33A-10T-8-30-17-4 65.608 2.799 65.608 2.799 3.166
U862-W-0.33A-10T-8-30-17-6 63.236 2.57 63.236 2.57 3.172
U862-W-0.33A-10T-8-30-17-7 59.097 2.26 59.097 2.26 3.312
U862-W-0.33A-10T-8-30-17-13 59.679 2.301 59.679 2.301 3.276
U862-W-0.33A-10T-8-30-17-15 61.67 2.382 61.67 2.382 3.424
Average 61.6 2.45 61.6 2.45 3.27
Std Dev 2.46 0.2 2.46 0.2 0.1
Count 6 6 6 6 6
0
10
20
30
40
50
60
70
0 0.005 0.01 0.015 0.02 0.025 0.03
Str
ess (
MP
a)
Strain (mm/mm)
U862-W-0.33A-10T-8-30-17
2
4
6
7
13
15
93
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