Effect of Crystalline Morphology of Long-Chain Branched Polypropylene for Film Capacitors on Dielectric Properties

The increase in conduction loss and the decrease of breakdown strength at high temperature are the bottlenecks restricting the application of polypropylene (PP) film capacitors. In this paper, long-chain branching modification and the addition of different nucleating agents (NA-21, DMDBS, WBG-II and TMB-5) were used to improve the dielectric properties of the films. The results show that the four nucleating agents can promote the nucleation of LCBPP and restrict the migration of charge carriers, thereby effectively reducing the conductivity loss and improving the breakdown strength of long-chain branched polypropylene (LCBPP). Among them, the NA-21 nucleating agent has the most significant improvement effect on the dielectric properties of LCBPP.