Electrical and Chemical Characterization of the Antioxidant Effects on Thermal Aging of Crosslinked Polyethylene (XLPE)

This article presents a comprehensive study on the impact of antioxidants (AOs) on the aging process of insulating polymeric materials, specifically complex permittivity, conductivity, and ac breakdown (BD) voltage. Accelerated aging was achieved through high temperatures (up to
$130~^{\circ }$
C) in the air on crosslinked polyethylene (XLPE) both with and without AOs. In addition to electrical tests, chemical analyses were performed to better understand the role of AOs during thermal aging. The results indicate that AOs effectively inhibit oxidation, preventing the formation of degradation species. As long as AOs are present, minimal changes in the electrical properties are observed. However, once the AOs are almost completely depleted, oxidation products significantly alter the electrical properties, resulting in a worsening of the material electrical performance.