Improved Conductivity and Breakdown Performance of Polypropylene Film by Parylene Blending for Power Capacitor
Haoliang Liu, Boxue Du, Meng Xiao, Zhaoyu Ran
Abstract
In this article, parylene doping method is proposed for enhancing the breakdown strength and reducing leakage conductivity of polypropylene (PP) films for power capacitors. The results indicate that 0.01 wt% parylene bulk doping PP membranes can reduce the leakage conductivity to 15%–27% at different temperatures. The breakdown strength is enhanced by 50% at 85 °C. The 0.05 wt% multilayer constructed doping membranes can further improve the dielectric properties, whose conductivity declines to 2% at 85 °C, with the same breakdown strength. Among all kinds of parylene additives, those with fluorine side groups exhibit the best electrical resistance, the conductivity of which is reduced to less than 1%. The multilayer constructed PP film presents advanced insulation performance with the charge injection being inhibited. The results provide a reference for structure optimization for film capacitors.