Charge formation in PE/Ionomer blends

It has been reported that the breakdown strength of polyethylene could be improved by mixing the ionomer into the PE [1]. A detailed study on the poling field dependence of the TSC with two types of PE/ ionomer blends, PE/Surlyn 1652 blends and PE/Surlyn 1601 blends, has shown a quite interesting phenomenon [2]. That is, the TSC of PE/ Surlyn 1652 blends increases as the poling field increases whereas that of PE/Surlyn 1601 blends decreases at high poling fields. An increase of the TSC with the poling field may be expected in the dielectrics, simply because the amount of electrons injected from the electrode and thus the amount of electrons trapped in the dielectric may increase at high poling fields. However, a decrease of the TSC at high poling fields cannot be readily explained. A decrease of the TSC at high poling fields may result from two possibilities: One is that the amount of charge injected and trapped becomes small at high poling fields, which may hold true when the homo-charges accumulated near the electrode act as "barrier" for the injection of more charges. The other is that the trapped charges migrate into the deeper region, so that the charging effect occurs when the trapped charges are released. Additional information on such charge-related properties as the electrical conduction and charge formation may be needed to confirm this. In this study, therefore, the charge formation and decay in PE/ionomer blends has been investigated to understand the different TSC behavior of these blends.