Effects of different factors on the heat and electrical conduction properties of carbon nanotube reinforced composite materials
14 Pages Posted: 17 Aug 2022
Date Written: August 8, 2022
The novel properties of carbon nanotubes have generated scientific and technical interest in the development of polymer matrix composite materials. In order to utilize carbon nanotubes in multi-functional material systems, it is crucial to investigate the effects of different factors on the heat and electrical conduction properties of carbon nanotube reinforced composite materials. This study explored the use of multi-walled carbon nanotubes as a conductive filler in an epoxy system. Electron microscopy was utilized to study the nanoscale evolution of nanocomposite structure during the manufacturing process. Carbon nanotube reinforced epoxy nanocomposites were processed with varying mass fractions of the reinforcement material and the heat and electrical conduction properties of the nanocomposites were determined. The network formation mechanism of carbon nanotubes in an epoxy matrix was discussed. The results indicate that the processing conditions for producing nanocomposites are fundamentally important. The nanocomposites exhibit significantly enhanced fracture toughness at low concentrations of carbon nanotubes. The thermal conductivity increases linearly with the concentration of carbon nanotubes to a maximum increase of about three times. The high aspect ratios of the carbon nanotubes are preserved during processing and enable the formation of an electrically conductive percolating network at very low carbon nanotube concentrations. The resulting electrical conductivity properties of the nanocomposites arise from the formation of macroscopic carbon nanotube aggregates. The electrical conductivity of the nanocomposites follows a percolation scaling law. The electrical conductivity of the nanocomposites follows a percolation scaling law with the critical mean concentration to form a conductive network of approximately 0.002% carbon nanotubes by weight in epoxy and a scaling law exponent of about 1.48. The processing conditions for producing nanocomposites need to be adjusted when trying to achieve low percolation thresholds in a manner appropriate to commercial applications.
Keywords: Carbon nanotubes; Composite materials; Thermal properties; Processing conditions; Electrical properties; Percolation theory
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