Effect of TiO2 Nanoparticles on the Electrical Aging Life of PP Cable Insulation Materials

Polypropylene (PP) as an environmentally friendly cable insulation material has become an emerging research topic in recent years. To improve the long-term operational stability of PP cables, this study aims to enhance the electrical aging life of PP by incorporating TiO2 nanoparticles through melt blending, both before and after surface treatment. The dispersion behavior of TiO2 in the PP matrix, the associated functional groups, and the crystallization characteristics of PP were characterized. In addition, polarization depolarization current (PDC) measurements were used to examine the effects of TiO2 on trap depth and density in the polymer. Accelerated electrical aging tests based on the inverse power law were conducted to predict the aging lifespan of TiO2/PP composites and to investigate how the surface treatment of TiO2 influences insulation performance through its effects on particle dispersion and trap distribution. The results indicate that the incorporation of nano-TiO2 effectively enhances the electrical aging lifespan of PP. However, high concentrations of untreated TiO2 lead to particle agglomeration, which reduces performance. Surface modification improves the dispersion of TiO2 in the PP matrix. Notably, adding 0.5wt% surface-treated TiO2 to PP results in the greatest improvement in electrical aging lifespan, as evidenced by a 17.02% increase in the electrical aging lifetime index compared to pure PP and a 14.32% increase compared to TiO2/PP composites containing the same concentration of untreated TiO2.