Characteristics of polymer insulator materials:: Voltage–lifetime characteristics of DGEBA/MDA/SN system

The voltage–lifetime characteristics of the new epoxy resin system, diglycidyl ether of bisphenol A (DGEBA)/4,4′-methylene dianiline (MDA)/succinonitrile (SN), have been investigated by using non-homogeneous electrode geometry. The lifetime dependence of the applied electric field well followed the empirical Vnt=const model. The lifetime factors at 25, 70 and 100°C were 5.128, 7.533 and 14.494, respectively. The dielectric breakdown mechanism at 25°C was changed around 14 kV. At high temperature, the thermal stress dominated the lifetime and at the low thermal stress, the thermal decomposition and distortion by electro-mechanical stress governed the dielectric breakdown under high electric field.