Effect of Curing and Functionalization on the Interface Thermal Conductance in Carbon Nanotube-Epoxy Composites

V Varshney and AK Roy and TJ Michalak and J Lee and BL Farmer, JOM, 65, 140-146 (2013).

DOI: 10.1007/s11837-012-0505-z

This study investigates the interface thermal conductance in a functionalized carbon nanotube (CNT)-epoxy composite system and how it is modified when the surrounding matrix is cured. We have used nonequilibrium molecular dynamics simulations to study the interface thermal conductance in both cured and uncured matrices, based on diglycidyl ether of bisphenol F (EPON-862) and diethylenetoluenediamine. The functionalization is modeled using a dynamic crosslinking algorithm and represents a realistic model of the matrix-filler interface. The thermal interface conductance increases linearly with the degree of functionalization up to the studied 2.5% due to stronger thermal coupling between functionalized CNT and the matrix. In addition, it was observed that curing of the matrix increases the interface conductance by 20% relative to the uncured matrix. This increase is attributed to an increase in thermal conductivity of cured epoxy resulting from relative enhancement in nonbonded interactions (originating from volume reduction) and structural rigidity during curing. Our results suggest that the interface conductance can be strongly influenced by the thermal properties of the bulk matrix as well as the interface chemistry of the additives such as CNTs.

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