Dynamic mechanical behaviours of epoxy insulating composites

A bisphenol-A epoxy/silica composite and a cycloaliphatic epoxy/silica composite are investigated for their dynamic mechanical properties. It is found that the glass transition of the epoxy composites can be detected by the change of dynamic storage modulus E´ and dissipation tanδ curves. For both materials, E´ experiences significant drop in the glass transition regions, while E´ below and above Tg shows little change with temperature. It is found that E´ and tanδ curves of the composites change dramatically with thermal aging. It is concluded that the dynamic mechanical properties of both types of epoxy composites change significantly during glass transition