Thermal conductivities and mechanical properties of epoxy resin as a function of the degree of cross-linking

Abstract

Epoxy resins are widely used polymer matrices for numerous applications. Despite substantial advances, the molecular-level knowledge-base required to exploit these materials to their full potential remains limited. A deeper comprehension of structure/property relationships in epoxy resins at the molecular level is critical to progressing these efforts. It can be laborious, if not impractical, to elucidate these relationships based on experiments alone, particularly in aiding the search for new, multi-functional resins. Here, molecular dynamics simulations are used to calculate, compare, and elucidate connections between both thermal conductivities and mechanical properties of an exemplar epoxy resin, Bisphenol F cross-linked with Diethyl Toluene Diamine, as a function of degree of cross-linking. Both the elastic modulus and thermal transport of the resin show an increase with greater cross-linking. Specifically, decomposition of the thermal conductivity into different force contributions suggests that although the bonded term contributes to an increase in the heat flux as a function of cross-linking, the contributions from non-bonded interactions suggest a less predictable trend. These outcomes provide a foundation for designing customized epoxy resins with both desirable thermal and mechanical attributes.