Partial discharge characteristics of epoxy resin-based nanocomposites fabricated with atomospheric plasma treated SiO2 nanoparticles

Favourable insulation properties can be obtained by the incorporation of nano-dimension particles into base polymer substances as the resultant large interface area between polymer molecules and nanoparticles alters the macro dielectric characteristics of the composite material. In this study, surface plasma treatment was carried out using atmospheric pressure glow discharge Helium plasma on silane-grafted SiO₂ nanoparticles before the fabrication of the nanocomposite. The surface energy of the particles was increased after such modification. Epoxy resin/SiO₂ nanocomposites were fabricated by employing untreated and treated nanoparticles respectively. Insulation performances of the nanocomposites were evaluated in terms of the resistance against partial discharge (PD) and the breakdown strength. Test results showed that the PD levels of the nanocomposites, both with untreated and plasma treated nano-fillers, were noticeably reduced compared to that of the pure epoxy resin sample. As a result, the electrical endurance of nanocomposite was improved. A higher PD inception and dielectric breakdown strength were also detected in nanocomposite samples. A comb-like spectrum was observed in the PD level trend of nanocomposites. Although the sample with plasma treated nanoparticles had a higher PD density, the endurance was noticeably reinforced over the one with the untreated SiO₂.