Effect of nanostructured SiO ₂ on charge capture performance and electrical ageing life of PP nanocomposites

Abstract To guarantee the reliability of high‐performance and environmentally friendly novel polypropylene (PP) for use as the primary insulation in cables, an assessment of the electrical ageing life of SiO 2 /PP composite materials was carried out using a step‐stress accelerated ageing test based on the inverse power law. The study involved an analysis of microstructural characteristics and performance testing to investigate the bonding between the SiO 2 under different surface treatment methods and matrixes. Furthermore, the impact of SiO 2 on charge capture performance in PP insulation was analysed through polarisation–depolarisation current testing. The results show that silica with long alkane chains and amino groups grafted on the surface has good compatibility with PP insulating layers, which can increase the trap energy level of captured electrons and thus reduce the damage of high‐energy electrons to the composites. SiO 2 increased the life index of the PP insulating layer by 19.95%, which contributed to the improvement of the electrical ageing life of the PP insulating layer.