Properties of grafting methyl acrylate on charge transport in polypropylene

This paper reports excellent electrical properties in polypropylene modified by grafting with methyl acrylate (PP-g-Met) and the related mechanism of the enhanced electrical properties. The crystal properties of PP-g-Met were analyzed. The influences of PP-g-Met on microstructure and electrical properties such as space charge accumulation, electrical breakdown strength, and DC conductivity were studied. Compared with pure PP, the PP-g-Met exhibits remarkably suppressed space charge injection, enhanced electrical breakdown strength and reduced conduction current. The mechanism enhancing the electrical properties can be explained that abundant deep traps are introduced by PP-g-Met with the introduction of acrylic acid, the spherulite structure of PP is destroyed by the acrylic acid branches, and the interfacial interaction is increased by the PP-g-Met. All the reason above reduce the charge mobility and raises the charge injection barrier to suppress space charge accumulation. This investigation would contribute to propose a new material modification strategy for designing high-voltage direct current insulation material.