The thermal conductivity of epoxy-resin / powder composite materials

Abstract

Thermal conductivity measurements have been taken between 2 and 300 K on composites made from an epoxy resin, Araldite MY 740, with powder fillers of glass spheres, quartz, corundum and diamond. Above about 10 K the conductivity of the composites is in good agreement with theory for the glass spheres, whilst for non-spherical particles the addition of a shape factor in the theory improves the agreement. Below 10 K the conductivity of the composite tends to be much lower than that predicted by the theory, and it can be appreciably less than the conductivity of the unfilled resin. This is shown to be due to the acoustic mismatch of phonons at the resin-particle interfaces.