Space charge dynamics in epoxy resin impregnated crepe paper multilayer under voltage polarity reversal

In this paper, the temporal space charge dynamics under both temperature and voltage polarity reversal of an epoxy resin impregnated crepe paper are characterized by pulsed electroacoustic method. It is found that the space charge injection and the interfacial traps located between the epoxy and paper plays an important role in determining the space charge dynamics. The results reveal that below 353 K, the calculated interfacial charge density is consistent with the Maxwell-Wagner (MW) model, while above 353 K, it is smaller than the measured value. The time constant during charging is much smaller than that predicted by the MW model and the space charge injection showed polarity effect, which leads to the interfacial charge densities under polarity poling voltage not being equal. It is proposed that the interfacial traps and space charge injection should be responsible for the observed space charge dynamics.