Conductivity and space in PE with additives

Temperature dependent conductivity and space charge formation was measured in metallocene catalyst polymerized polyethylene samples of planar geometry with semiconductive electrodes. The temperature dependence of the conductivity was determined based on leakage current measurements at variable temperatures. Space charge formation under an applied electrical field of 20 kV/mm was investigated by means of the pulse-electro-acoustic method (PEA) at room temperature. The results were compared to space charge formation and conductivity in common LDPE. The measurements showed considerable differences between materials and only minor influence of crosslinking process and the addition of antioxidant with respect to the electrical properties of the material. Possible correlations between conductivity and space charge formation are discussed in the paper. The relevance of the findings for application to extruded high voltage cables will be discussed.