Deterioration by partial discharges of polyethylene in oxygen containing gas atmosphere

To study the deterioration of LDPE by PD (partial discharge), experiments were conducted using the CIGRE II type electrode in N₂ (pure nitrogen) and (N₂+O₂) gas atmosphere. After being subjected to the PD, specimens were examined by AFM (Atomic Force Microscope). The AFM image clearly revealed the creation of pits on the surface of LDPE specimen. A big difference in the pattern of pits was observed between the specimen subjected to the PD in N₂ and to the PD in (N2+O2). The FTIR spectra detected in the specimen subjected to the PD in (N₂+O₂) showed that carbonyl compounds were produced on the surface of the deteriorated LDPE. The oxidative degradation is presumed to be the dominant process of the deterioration of LDPE by PD in oxygen containing atmosphere