Electrical Analyses of Gamma Radiation-Induced Aging on EPDM-Based Insulation Systems

This paper deals with the investigation of the insulating properties of EPDM materials subjected to radiation aging with two non-destructive techniques: electrical (dielectric spectroscopy) and chemical (FTIR). Flat samples of EPDM were subjected to accelerated aging at 860 Gy/h for 664 h with four withdrawals at room temperature. The dielectric spectroscopy results indicate that the tan δ at 100 kHz coherently follows the aging evolution of the materials and it is suggested to be a suitable aging marker. The spectra of FTIR results suggest that EPDM undergoes chain scission and oxidation after radiation ageing. These results confirm the suitability of the electrical nondestructive technique for aging evaluation.