Some consideration of voltage-induced interfacial space charge in several laminated dielectrics

Some theoretical consideration is given for voltage-induced interfacial space charge in several laminated dielectrics which was measured by the laser induced pressure pulse (LIPP) method and the pulsed electroacoustic (PEA) method. A low density polyethylene sheet was laminated by several kinds of materials such as ethylene vinyl acetate, ethylene propylene copolymers, ethylene propylene-diene terpolymers with the diene components of dicyclospentadiene and ethylenepropylene diene terpolymers with 5-ethylidene-2-norbornene. Interfacial space charge formed in such dielectrics by application of dc voltage and its decay process are evaluated and analyzed in term of permittivity and electrical conductivity of the materials used. Two or three decay time constants are obtained for each of the laminates and are correlated with the electrical and dielectric properties of the dielectrics used.