Study on the improvement of the insulation performance of polypropylene film by regulating TiO₂–F by liquid phase grafting

Abstract

According to the problem that the performance of film capacitors is limited due to the poor insulation of polypropylene film, a new nano-filler was studied and a polypropylene composite dielectric was fabricated. The breakdown strength of composite dielectrics was measured and the mechanism for improving their insulation properties was analyzed. In this paper, TiO2 with high dielectric constant is plasma-treated and then coated with a layer of polypropylene shell. TiO2 increases the dielectric constant of polypropylene film composite dielectrics, and shell-like polypropylene makes TiO2 more tightly bound to the polypropylene matrix. Compared with pure PP, the breakdown voltage of TiO2-F is increased by 18.7%, and the breakdown voltage of TiO2-F@PP-mah is increased by 40.5%, and the new nano filler greatly improves the insulation performance of PP. The experimental results show that TiO2 introduces a low-density trap, TiO2-F introduces a high-density deep trap, and the modification of PP-mah slows down the dielectric constant conflict, increases the compatibility between the nanoparticles and the matrix, and increases the trap energy level. Based on the analysis of experimental results with different mass fractions, this paper proposes the optimal filling ratio of the new core-shell, which provides a new method for the composite dielectric to improve the insulation performance.