Accumulation and decay processes of interfacial charge in LDPE/EVA laminated film

Accumulation and decay processes of interfacial charges in the LDPE/EVA laminated film have been studied from space charge distributions measured using a pulse electroacoustic (PEA) method. When DC voltage is applied to the laminate film composed of two kinds of different dielectrics, space charges produced due to voltage application will be accumulated at the interface of two dielectrics, and create the electric field distortion in the specimen. In this case of applying DC voltage to the laminated film, the positive charges injected from EVA side are accumulated at the interface between LDPE and EVA. After the circuit is shorted, space charges accumulated decrease gradually with two kinds of time constants. Finally, it is found that two time constants are caused due to the difference between the resistivity of LDPE and that of EVA