Hindered Phenolic Compound Grafting Modification and Space Charge Investigation of PP Cable Insulation

This paper explores the impact of grafting molecule types on the physicochemical and insulation properties of polypropylene (PP) cables. Two molecules without hindered phenolic groups are selected as comparative samples. Three types of grafted polypropylene insulation samples are prepared, and the electrical conductivity, space charge characteristics, and direct current breakdown characteristics of polypropylene under direct voltage are studied. The results indicate that hindered phenolic compounds can significantly mitigate the conductivity of polypropylene at elevated temperatures compared to the other two grafted small molecules. In space charge experiments, the grafted modified materials exhibit reduced quantities of space charge, leading to higher breakdown field strengths. This indicates that hindered phenolic compounds can increase trap density, reduce the number of hot electrons, avoid molecular chain damage, and thus extend the insulation life of PP.