Modelling the thermal conductivity of epoxy nanocomposites with low filler concentrations

Polymers are the preferred insulating materials for several electrical applications due to their ease of production, light weight and low cost. However, their low thermal conductivity constitutes a bottleneck and efforts are made to increase it. An approach to improve heat transfer through polymers is the addition of nanosized or/and microsized fillers with relatively high thermal conductivity. In this paper, three dimensional models were developed with the use of the finite element software Comsol Multiphysics 4.3 in order to simulate different polymeric nanocomposites based on epoxy and estimate their thermal conductivity. An interfacial layer with a thickness of 10 nm was considered around the particles. The assumption of an interfacial layer leads to results which are closer to the experimental results only when the particles are surface treated. In case of unmodified particles, the consideration of an interfacial layer results in higher values than the experimental results. The developed models demonstrate the important role of interfaces and strengthen the hypothesis that reorganization of the polymer matrix takes place when surfactants are used.