Research on Thermal Aging Characteristics of Copolymer‐Modified Polypropylene Cable Insulation Materials

ABSTRACT To explore the long‐term service characteristics of copolymer‐modified polypropylene (PP‐co‐PE) cable insulation materials, their thermal aging behavior was systematically studied. Through multi‐temperature accelerated thermal aging tests, the evolution of material properties across different aging stages was analyzed. The study encompassed the electrical, thermal, mechanical, and physicochemical characteristics. Concurrently, key parameters such as the thermal decomposition temperature, tensile strength, and breakdown strength were examined to determine their relationship with aging time. The results showed that the thermal decomposition temperature increased during the initial stages of aging, which can be used as an effective criterion for early aging. When the material undergoes a yellowing reaction, its tensile strength significantly decreases, which can be used as a basis for judging the end of life. Moreover, the breakdown strength continuously decreases during the aging process, which is a key indicator for evaluating the degree of aging. The study also found that the material undergoes a transformation from nonpolar to weakly polar during the aging process, which is the main reason for performance deterioration. This study provides a theoretical basis and data support for engineering applications and life prediction of PP‐co‐PE cable insulation materials.