Crystallisation regulation of long‐chain branched polypropylene on dielectric performance and energy density for metallised film capacitors

Abstract The degradation of dielectric properties polypropylene (PP) at high temperature affects the operational stability metallised film capacitors. This study presents a method to improve high‐temperature performance PP through long‐chain branching modification and regulating crystalline properties. Different amounts nucleating agents were added branched (LCBPP) effect crystallisation on electrical results show that branches thermal by enhancing chain entanglement, also increase number crystals due heterogeneous nucleation. addition promotes LCBPP, which increases nucleation density improves crystallinity. regulation microstructure suppresses relaxation chains limits charge transport. constant modified films with is slightly increased, doping has little loss LCBPP. At 125°C, conductivity LCBPP 0.05 wt% agent decreased 2 orders magnitude breakdown strength increased 26.3%. implications for improving films.