Effects of Antioxidant Co-Blending on Crosslinking and Aging Performance of XLPE Cable Insulation Materials

This study investigates the effects of hindered phenolic antioxidant (AO1), thio-biphenolic antioxidant (AO2), and their synergistic combination on the crosslinking and aging performance of extruded crosslinked polyethylene (XLPE) cable insulation materials. Four XLPE formulations with distinct antioxidant systems were prepared via melt blending, and their crosslinking kinetics, crosslinking density, thermooxidative resistance, aging degradation, and dielectric properties were systematically evaluated. The results demonstrate that, under equivalent loading levels, the thiobiphenolic antioxidant AO2 exhibits significant inhibition of scorching behavior in XLPE while demonstrating superior thermo-oxidative aging resistance. However, its incorporation reduces the crosslinking density and increases dielectric loss of the polymer matrix. In contrast, the synergistic antioxidant system (AO1/AO2) at a lower total concentration not only maintains high crosslinking efficiency and low dielectric dissipation factor but also enhances scorch suppression and antioxidant efficacy. This research provides valuable insights for the development of high-voltage XLPE cable insulation materials, highlighting the pronounced advantages of antioxidant synergism in optimizing comprehensive material performance.