Investigation of dielectric properties and methylene intactness under multiple environmental stresses for high voltage epoxy composites

Abstract

Epoxy decays its dielectric characteristics and exhibits degradation of main hydrocarbon on exposure to multiple environmental stresses. Inorganic oxides-based epoxy composites have been performingwell in many applications and short-term testing; therefore, evaluation of their dielectric and structural characteristics under extreme weathering conditions may also unleash enhancement in these characteristics. To explore dielectric properties and degradation of main hydrocarbon group, neat epoxy and silica-based epoxy microcomposite (15% micro-silica loading) and nanocomposites (5% nano-silica loading)have been prepared and subjected to acid rain, heat, ultra-violet radiation, salt fog, and humidity in a chamber that was specially fabricated in view ofservice conditions. Interesting results were obtained before and after aging. Enhanced intactness of methylene group was observed in nanocomposite followed by micro composite. Similarly, for epoxy nanocomposites not only higher dielectric constant, lower energy dissipation and conductivity was recorded before application of stresses, but also nanocomposite showed superior sustainability in these properties after aging. In all analyses, microcomposites performed better than neat epoxy but in conductivity the results of both samples were found comparable.