Correlation between mechanical and dielectric relaxation processes in epoxy resin composites with nano- and micro-fillers

Effects of addition of nano-sized and micro-sized fillers into epoxy resin on its mechanical and dielectric relaxation phenomena were examined. The glass transition temperature (T _g) decreased when a small content of nanoclay modified by octadecylamine was added, but the decrease in T _g was suppressed when the nanoclay was modified by dimethyldodecylamine. On the other hand, T _g increased when an abundant amount of microsilica was added. At temperatures above T _g, both mechanical and dielectric relaxations were accelerated in samples with octadecylamine-modified nanoclay, while the acceleration did not occur in samples with nanoclay modified by dimethyldodecylamine. Both relaxations were restricted in composites with abundant microsilica. Therefore, co-addition of dimethyldodecylamine-modified nanoclay and abundant microsilica is adequate in order to make an epoxy resin composite with a high T _g and low dielectric loss. ©2012 Wiley Periodicals, Inc. Electron Comm Jpn, 95(9): 1-9, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.11420