Effect of percolation and interfacial characteristics on breakdown behavior of nano-Silica/Epoxy composites

The characteristics of electrical breakdown in inorganic nano-Silica/Epoxy composites are studied. Nano Silica shows significant impact on electrical breakdown strength of nano-Silica/Epoxy composites. Appropriate proportion of inorganic nano Silica can improve the breakdown strength of the composites, but excessive fillers show opposite effect. The percolation and interfacial characteristics are used to interpret the peak value appeared on the curve of breakdown behavior of the nano-composites. The interfaces between nano-particles and Epoxy matrix decide the formation of percolation network. In addition, modified nano Silica particles with silane coupling agent are effective to form the interactions of molecular between nano-particles and Epoxy. As a result, the breakdown strength of nanocomposites higher than pure Epoxy, and the breakdown strength of modified Silica nano-composites higher than the unmodified one. The percolation threshold of 5wt% Silica content in the nano-Silica/Epoxy composites is founded.