Dynamic mechanism of breakdown in polypropylene-based nano-dielectric

The dynamic mechanism of breakdown in polypropylene (PP) were represented based on the discharge-avalanche theory. PP is a typical semi-crystalline thermoplastic polymer with low loss and high thermal stability, which had broad application prospects in recyclable and environment-friendly insulation. Dielectric strength was one of the important properties for polymer insulation, hence research of breakdown mechanism was of great significance for insulation reliability increase and advanced materials development. In this paper, the dielectric strength of PP was enhanced by nano-silica filling, and mechanism of enhancement was discussed based on the change of activation energy measured by thermally stimulated depolarization currents (TSDC).