Influence of zinc oxide nanoparticles on flashover voltage of unsaturated polyester resin-based composites for electrical insulators

Introduction. Polyester-based composites are increasingly used in electrical applications for their insulation, mechanical, and thermal properties. Nanofillers have shown promise in enhancing the properties of polymer-based composites. Goal. This study aims to improve the flashover voltage of unsaturated polyester resin (UPR)-based composites by incorporating zinc oxide (ZnO) nanoparticles. Methodology. UPR/ZnO nanocomposites were prepared with various ZnO nanofiller ratios (0 %, 1 %, 3 %, 5 %, and 7 % by weight) with different sample lengths (0.5, 1.5, 2, and 2.5 cm). The flashover voltage was measured for the pure UPR sample and each composition of the studied filler ratios at various sample lengths. X-ray diffraction analysis was performed. A curve-fitting method was applied to estimate the flashover voltage of UPR/ZnO nanocomposites containing intermediate filler ratios between those experimentally tested. Results. Incorporation of ZnO nanofillers significantly enhanced the flashover voltage of polyester-based nanocomposites. The pure UPR sample exhibited the lowest flashover voltage, whereas the composite with 7 wt.% ZnO nanofiller demonstrated the highest. Notably, increasing