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 (Tg) decreased when a small content of nanoclay modified by octadecylamine was added, but the decrease in Tg was suppressed when the nanoclay was modified by dimethyldodecylamine. On the other hand, Tg increased when an abundant amount of microsilica was added. At temperatures above Tg, 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 Tg and low dielectric loss. (c) 2012 Wiley Periodicals, Inc. Electron Comm Jpn, 95(9): 19, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.11420