Effect of silica concentration on electrical conductivity of epoxy resin–carbon black–silica nanocomposites

Electrical properties of nanocomposites are determined by the conductive paths of carbon black and influenced by a “network” of silica. With increasing content of silica, carbon black (CB) particles are optimally dispersed, contributing to the generation of a conductive network between CB particles via direct particle contact and a tunneling effect; maximum conductivity for the epoxy resin–CB–silica nanocomposite described herein occurs at a ratio of 0.6:1.0 (SiO2:CB). As a non-conductive component, excessive silica will prevent electron flow, giving rise to low conductivity.