Improvement on Partial Discharge Resistance of Epoxy/Al2O3 Nanocomposites by Irradiation With 7.5 MeV Electron Beam

Epoxy resin used as insulating material in electrical and electronic devices is often subjected to a great risk of deterioration induced by partial discharge (PD). The resistance to PD becomes a key factor that influences the lifetime of the epoxy resin. Nano-sized inorganic filler doping has been reported to have a positive effect on improving the PD resistance by forming epoxy based nanocomposites with proper type and content of nano-fillers. In this work, attempts have been made to further improve the PD resistance of epoxy nanocomposites through high energy irradiation method. The epoxy/Al
₂
O
₃
nanocomposites have been prepared with the filler content of 4 wt%. The neat epoxy and the nanocomposites were both irradiated by a 7.5 MeV electron beam with the total dose of 500 kGy. PD erosion of the material was introduced by means of needle-to-plate electrode system, and the PD resistance was estimated through the measurement of maximum erosion depth occurring on the sample surface. Frequency dependent relative permittivity, scanning electron microscopy, differential scanning calorimetry, and fourier transform infrared spectrum have been employed to assist in the analysis of radiation induced variation in sample’s resistance to PD. Obtained results indicated that after irradiated by the electron beam with 500 kGy, the samples exhibited remarkable enhancement in PD resistance compared with the un-irradiated samples. It suggests that the PD resistance of the nanocomposites is dependent upon the molecular structure of the base polymer, which could be modified by the irradiation induced crosslinking reaction.