University of Manchester
1.
Cao, Gaoxiang.
Multi-functional epoxy/graphene nanoplatelet
composites.
Degree: 2016, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:301217 
Graphene nanoplatelets (GNP) with thickness of 6 ~
8 nm and lateral dimension of 5 μm (M5) and 25 μm (M25) have been
used to prepare epoxy composites. Epoxy composites were fabricated
initially by shear mixing to investigate the effects of filler type
on the structure and properties of composites. The complex
viscosity of GNP-epoxy mixture was found to increase by almost
three orders of magnitude going from the neat epoxy to the 8 wt.%
loading, leading to difficulties in their processing. Scanning
electron microscopy of the composites showed that both fillers
aggregated at high loadings with the M25 buckling more easily due
to its larger diameter, which compromises its aspect ratio
advantage over M5, resulting in only slightly better mechanical
performance. Polarized Raman spectroscopy revealed that both M5 and
M25 were randomly distributed in the epoxy matrix, After adding M5
and M25 fillers, the storage modulus increase with the filler
loadings, however, the glass transition temperature (Tg) drops
slightly after initial incorporation, then rises with further
filler addition attributed to the pin effects of filler
aggregations. In terms of electrical property, M25 has lower
percolation (1 wt.%) than M5 composites due to its bigger aspect
ratio, which enable M25 to form a conductive network more
efficiently. Furthermore, M25 composites also have slightly better
thermal and mechanical properties over that of M5 composites.
However, the difference is not significant considering the aspect
ratio of M25 is five times of that of M5. The reason is that the
aggregation and buckling of M25 compromise its advantage over M5.
Due to the better performance of M25 as filler, M25/epoxy
composites were prepared by shear mixing, solvent compounding and
three-roll mill. Samples made by solvent compounding display the
lowest percolation threshold (0.5 wt.%), related to its relatively
uniform dispersion of M25 in matrix, resulting in higher thermal
conductivity and better mechanical properties. Water uptake in a
water bath at 50 °C took 75 days to be saturated. Higher loaded
samples have lower diffusion coefficient because of the barrier
effects of GNP fillers, but have higher maximum water absorbed,
which is owing to filler aggregation. Properties test of aged and
unaged specimens show thermal conductivity of the aged was enhanced
due to water’s higher thermal conductivity than epoxy resin matrix,
while electrical performance was compromised due to the swelling
effects caused by absorbed water. The mechanical properties of aged
samples also dropped slightly due to plasticization
effects.
Advisors/Committee Members: YOUNG, ROBERT RJ, Young, Robert, Kinloch, Ian.Subjects/Keywords: Eopxy; Graphene nanoplatelet; composites; Impedance
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APA (6th Edition):
Cao, G. (2016). Multi-functional epoxy/graphene nanoplatelet
composites. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:301217
Chicago Manual of Style (16th Edition):
Cao, Gaoxiang. “Multi-functional epoxy/graphene nanoplatelet
composites.” 2016. Doctoral Dissertation, University of Manchester. Accessed April 16, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:301217.
MLA Handbook (7th Edition):
Cao, Gaoxiang. “Multi-functional epoxy/graphene nanoplatelet
composites.” 2016. Web. 16 Apr 2021.
Vancouver:
Cao G. Multi-functional epoxy/graphene nanoplatelet
composites. [Internet] [Doctoral dissertation]. University of Manchester; 2016. [cited 2021 Apr 16].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:301217.
Council of Science Editors:
Cao G. Multi-functional epoxy/graphene nanoplatelet
composites. [Doctoral Dissertation]. University of Manchester; 2016. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:301217
University of Manchester
2.
Cao, Gaoxiang.
Multi-functional epoxy/graphene nanoplatelet composites.
Degree: PhD, 2016, University of Manchester
URL: https://www.research.manchester.ac.uk/portal/en/theses/multifunctional-epoxygraphene-nanoplatelet-composites(b4991dc7-b156-4628-9fcd-425d41a6b8e8).html
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694296
Graphene nanoplatelets (GNP) with thickness of 6 ~ 8 nm and lateral dimension of 5 μm (M5) and 25 μm (M25) have been used to prepare epoxy composites. Epoxy composites were fabricated initially by shear mixing to investigate the effects of filler type on the structure and properties of composites. The complex viscosity of GNP-epoxy mixture was found to increase by almost three orders of magnitude going from the neat epoxy to the 8 wt.% loading, leading to difficulties in their processing. Scanning electron microscopy of the composites showed that both fillers aggregated at high loadings with the M25 buckling more easily due to its larger diameter, which compromises its aspect ratio advantage over M5, resulting in only slightly better mechanical performance. Polarized Raman spectroscopy revealed that both M5 and M25 were randomly distributed in the epoxy matrix, After adding M5 and M25 fillers, the storage modulus increase with the filler loadings, however, the glass transition temperature (Tg) drops slightly after initial incorporation, then rises with further filler addition attributed to the pin effects of filler aggregations. In terms of electrical property, M25 has lower percolation (1 wt.%) than M5 composites due to its bigger aspect ratio, which enable M25 to form a conductive network more efficiently. Furthermore, M25 composites also have slightly better thermal and mechanical properties over that of M5 composites. However, the difference is not significant considering the aspect ratio of M25 is five times of that of M5. The reason is that the aggregation and buckling of M25 compromise its advantage over M5. Due to the better performance of M25 as filler, M25/epoxy composites were prepared by shear mixing, solvent compounding and three-roll mill. Samples made by solvent compounding display the lowest percolation threshold (0.5 wt.%), related to its relatively uniform dispersion of M25 in matrix, resulting in higher thermal conductivity and better mechanical properties. Water uptake in a water bath at 50 °C took 75 days to be saturated. Higher loaded samples have lower diffusion coefficient because of the barrier effects of GNP fillers, but have higher maximum water absorbed, which is owing to filler aggregation. Properties test of aged and unaged specimens show thermal conductivity of the aged was enhanced due to water’s higher thermal conductivity than epoxy resin matrix, while electrical performance was compromised due to the swelling effects caused by absorbed water. The mechanical properties of aged samples also dropped slightly due to plasticization effects.
Subjects/Keywords: 620.1; Eopxy; Graphene nanoplatelet; composites; Impedance
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Cao, G. (2016). Multi-functional epoxy/graphene nanoplatelet composites. (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/multifunctional-epoxygraphene-nanoplatelet-composites(b4991dc7-b156-4628-9fcd-425d41a6b8e8).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694296
Chicago Manual of Style (16th Edition):
Cao, Gaoxiang. “Multi-functional epoxy/graphene nanoplatelet composites.” 2016. Doctoral Dissertation, University of Manchester. Accessed April 16, 2021.
https://www.research.manchester.ac.uk/portal/en/theses/multifunctional-epoxygraphene-nanoplatelet-composites(b4991dc7-b156-4628-9fcd-425d41a6b8e8).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694296.
MLA Handbook (7th Edition):
Cao, Gaoxiang. “Multi-functional epoxy/graphene nanoplatelet composites.” 2016. Web. 16 Apr 2021.
Vancouver:
Cao G. Multi-functional epoxy/graphene nanoplatelet composites. [Internet] [Doctoral dissertation]. University of Manchester; 2016. [cited 2021 Apr 16].
Available from: https://www.research.manchester.ac.uk/portal/en/theses/multifunctional-epoxygraphene-nanoplatelet-composites(b4991dc7-b156-4628-9fcd-425d41a6b8e8).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694296.
Council of Science Editors:
Cao G. Multi-functional epoxy/graphene nanoplatelet composites. [Doctoral Dissertation]. University of Manchester; 2016. Available from: https://www.research.manchester.ac.uk/portal/en/theses/multifunctional-epoxygraphene-nanoplatelet-composites(b4991dc7-b156-4628-9fcd-425d41a6b8e8).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694296
Open Access Theses and Dissertations