Effect of Fillers on Electrical Conductivity of Epoxy Composites

This paper reports, electrical conductivity studies carried out on RT cure epoxy resin (LY556+HY951) containing three different particulate fillers graphite (Gr) a soft material, silicon carbide (SiC) a hard material and a hybrid graphite and silicon carbide (Gr-SiC). The weight fractions of three different fillers were varied from 10% to 40 wt% in steps of 10%. Increased filler fraction increases the electrical conductivity of epoxy composites for all the three types of fillers. The improvement in thermal conductivity for the epoxy hybrid composite containing 20% SiC, 20% Gr and 60% epoxy is 2.5 times higher than neat epoxy. Significant improvement in the electrical conductivity is observed for 40% filled epoxies. The experimental results were compared with analytical models such as Maxwell-Wagnor and also with Wideman-Franz law which relates thermal and electrical conductivity. The experimental thermal conductivity exhibits good correlation with analytical equations.