Effect of nano-Al2O3 and micro-Al(OH)3 co-doping on epoxy resin properties

Several abnormal sound or flashover on epoxy tri-post insulator had caused failures of 500kV GIL in Guangdong Power Grid during 2019-2020. Epoxy based inorganic nanocomposites have drawn much interest in the field of electrical equipment. After filling in nanoparticles, the electrical, thermal and mechanical properties of epoxy resin will be increased apparently. With micron fillers in nanocomposites, the interfacial defects of composites could be reduced and thus improve the properties further. In this paper, tensile strength, thermal decomposition, and AC electrical strength of epoxy co-doping composites with different content and size of nano-Al
₂
O
₃
and micro-Al(OH)
₃
fillers were analyzed. The effects of both fillers and co-doping ratio in composites were discussed. It was found that low content of nanoparticles could improve the thermal, mechanical and electrical properties of epoxy. With 10 wt% micron particles, the positive effects of nanoparticles were enhanced, while more micron particles would depress the properties. Smaller micron particles had better effects on micro/nano-composites.