Study on the Polarity of Residual Voltage in Polymeric Insulating Films

Abstract

Residual voltages were measured for seven kinds of polymeric insulating films with brass or evaporated silver electrodes at room temperature. When the circuit was opened at the cathode side, the negative residual voltage was always observed in polyethylene terephthalete (PET), polycarbonate (PC), polystylene (PS) and polypropylene (PP) regardless of the experimental conditions. The positive residual voltage was ovserved in low-density polyethylene (LDPE), high-density polyethylene (HDPE) and ethylene and vinylacetete copolymer (EVA) under conditions which would bring about a double injection.