Eco-Friendly Hybrid Composite Fillers for High-Performance Epoxy Insulators: Advancing Thermal and Electrical Durability

The increasing demand for high power due to urbanization requires a stable supply of electrical energy and the development of insulating composites with high heat resistance and insulating properties. Epoxy is a typical insulating polymer used in various industries, especially as a resin for gas-insulated switchgear (GIS) spacers. In this study, a hybrid fusion microfillers (HMFFs) with a core–shell structure were synthesized by the mechano-fusion method with zinc oxide (ZnO) and alumina (Al2O3) fillers to improve the mechanical strength and dielectric strength of epoxy. By combining heterogeneous particles into a single particle, HMFFs developed a structure of insulating particles with improved heat resistance and insulating properties. The epoxy insulating composite with HMFFs induced the dispersion of energy flow, which improved the durability of the resin, as well as the mechanical strength and dielectric strength. In addition, the insulation composite with stable tensile and flexural strength properties even at high temperatures of 80 °C suggests that it can be used as the main insulating composite for GIS to ensure stable transmission of high-current electric energy.