Improvement in high-temperature dielectric properties of epoxy resin by abundant addition of micro-silica

Effects of addition of micro-sized silica fillers and/or nano-sized clay fillers into epoxy resin on its dielectric properties were examined. The glass transition intermediate temperature (T_g) was found to show a decrease by the addition of a small amount of nanofillers, while it is increased by the addition of abundant microfillers with and without co-addition of a small amount of nanofillers. At temperatures above T_g, the samples with abundant microfillers were added have low conductivity, low dielectric constant, and low dielectric loss factor regardless of the co-addition of nanofillers.