GC-MS and FTIR analysis of LDPE and XLPE deteriorated by partial discharge

To study the mechanism of deterioration by partial discharge (PD) of low density polyethylene (LDPE) and cross-linked polyethylene (XLPE), experiments were conducted to measure the gas components produced during deterioration by PD. Experiments were performed using an experimental system having voltage application apparatus and equipped with gas measuring system with incorporated gas chromatograph-mass spectrometer (GC-MS). Results of these experiments showed that CO₂ is produced when LDPE is subjected to PD in an oxygen-containing atmosphere. The amount of carbon dioxide was found to increase concomitant with the period of voltage application and oxygen content in the area where PD occurs. Taking account of Flourier transform infrared spectrophotometer (FTIR) analysis results for deteriorated LDPE and XLPE in previous experiments, the process of deterioration by PD, together with the antioxidant action on the deterioration, are discussed.