Effect of thermal aging on the electrical properties of crosslinked polyethylene

This article reports on the effect of thermal aging on the electrical properties of crosslinked polyethylene (XLPE) used in high voltage cables. It was shown that thermal aging modifies the electrical properties of the polymer. The degradation is accelerated when the temperature is increased. This degradation is due to a thermooxidation, followed by a loss of antioxidant, and a change in color of the material. At 80 and 100°C, the antioxidant is practically efficacious during the aging, whereas at 120 and 140°C, it is consumed after 1500 and 1000 h, respectively, which results in an increase in the dielectric losses and a diminution in the volume resistivity.