Improvement of the Electrical-Mechanical Performance of Epoxy/Graphite Composites Based on the Effects of Particle Size and Curing Conditions

Abstract

This study aims to improve the electrical-mechanical performance of traditional epoxy/graphite composites for engineering applications. The improvement in the properties of these composites depended on the incorporation of different sizes of graphite particles of the same type and controlling their curing process conditions. The thermal properties and microstructural changes were also characterized. A maximum in-plane electrical conductivity value of approximately 23 S/cm was reported for composites containing 80 wt.% G with a particle size of 150 µm. The effect of combining large and small G particles increased this value to approximately 32 S/cm by replacing the large particle size with 10 wt.% smaller particles (75 µm). A further increase in the electrical conductivity to approximately 50 S/cm was achieved due to the increase in curing temperature and time. Increasing the curing temperature or time also had a crucial role in improving the tensile strength of the composites and a tensile strength of ~19 MPa was reported using a system of multiple filler particle sizes processed at the highest curing temperature and time compared to ~9 MPa for epoxy/G150 at 80 wt.%. TGA analysis showed that the composites are thermally stable, and stability was improved by the addition of filler to the resin. A slight difference in the degraded weights and the glass transition temperatures between composites of different multiple filler particle sizes was also observed from the TGA and DSC results.

Current status of research on composite bipolar plates for proton exchange membrane fuel cells (PEMFCs): nanofillers and structure optimization

“…Structure optimization through reasonable methods can improve the performance of composite bipolar plates without changing the graphite/resin raw material ratio. At present, the main directions of structural optimization are: (1) optimization of the dispersion pattern of graphite/ resin, [104][105][106][107] i.e., through physical or chemical means, articially control the dispersion pattern between graphite/resin phases, so that the composite bipolar plate has a strategic distribution of graphite-resin, (2) optimization of the electrically conductive network of the composite bipolar plate: [108][109][110] through the design of electrically conductive paths of the composite bipolar plate, so that the composite bipolar plate has the overall electrically conductive network structure. (3) Interfacial modication and surface functionalization of the llers of the composite bipolar plate 111,112 to enhance the bonding force between the interfaces of the composite bipolar plate and the wettability between the graphite-resin.…”

“…At present, the main directions of structural optimization are: (1) optimization of the dispersion pattern of graphite/resin, 104–107 i.e. , through physical or chemical means, artificially control the dispersion pattern between graphite/resin phases, so that the composite bipolar plate has a strategic distribution of graphite–resin, (2) optimization of the electrically conductive network of the composite bipolar plate: 108–110 through the design of electrically conductive paths of the composite bipolar plate, so that the composite bipolar plate has the overall electrically conductive network structure.…”

Polymer based flow field plates for polymer electrolyte membrane fuel cell and the scope of additive manufacturing: A techno‐economic review

“…Due to their low contact resistance and the absence of passive film, carbon‐based composite plates have several advantages for PEMFCs. However, due to their inadequacy in mechanical strength and hydrogen permeability, the production of thin FFPs has been hampered for mobility applications 52 . As FFP materials, carbon/carbon composites have been investigated several times in an attempt to meet DoE standards for PEMFCs 53 .…”

“…However, due to their inadequacy in mechanical strength and hydrogen permeability, the production of thin FFPs has been hampered for mobility applications. 52 As FFP materials, carbon/carbon composites have been investigated several times in an attempt to meet DoE standards for PEMFCs. 53 Table 2 54 illustrates the relative characteristics of graphite/polymer composite FFPs in a bid to gain a clear-cut grasp of their features and performance.…”

Investigation of laser micro-drilling machinability and performance optimization of polymer nanocomposites reinforced with different carbon allotropes

“…It is known for its excellent thermal conductivity and strength properties and known as a low-cost prospective filler in multifunctional composites. [8][9][10][11] CNTs are graphitic carbon tubes that are molecule-scale and have extraordinary mechanical, thermal, and electrical capabilities. 12,13 The CNTs are established to be the most suited composite's reinforcements when compared to other carbon materials owing to their comparatively lower density (2.1 g/cm 3 ) along with higher tensile modulus (1 TPa) and strength (10 GPa) and exploited in a wide range of industrial applications.…”