Effect of Functional Grafting on Breakdown Strength and DC Conductivity of Polypropylene Blend Insulation

Blending polypropylene (PP) with polyolefin elastomer (POE) is a conventional method for improving mechanical characteristics in cable insulation. However, such blends often suffer from diminished electrical properties. To address this challenge, this study investigates the impact of functional grafting on the dielectric properties of PP blend insulation. Through experimental characterization, the synergistic effects of functional grafting and elastomer blending on the dielectric behavior and mechanical properties of PP are analyzed. The introduction of polar groups during the 3052 grafting process in PP generates deep traps, effectively trapping charge carriers and mitigating their migration, thereby reducing DC volume conductivity. Moreover, 3052 grafting significantly hinders space charge accumulation in PP blend insulation, with PP-3 demonstrating the most effective suppression of space charge injection. Additionally, incorporating 3052 into the PP blend insulation notably enhances its DC breakdown strength. Among the samples tested at the same temperature, PP-3 exhibits the highest DC breakdown strength, indicating superior insulating properties.