Insulation properties of PP based copolymer with polar group and inorganic filler

Polypropylene (PP) is one of the candidate materials for cable insulation instead of XLPE, which is remarked as a thermoplastic material with high melting temperature. In our previous studies, it is shown that space charge injection and conduction current in PP based flexible copolymers are both reduced at high temperatures and under high DC electric fields by adding an inorganic filler or a polar group into them. In this report, we tried to analyze the state of trap sites formed in the PP copolymers using the quantum chemical calculation to understand the effect of the inorganic filler and the polar group added into PP copolymers.