Treeing Breakdown Property in Epoxy/TiO2 Nanocomposites

Additives and fillers are traditionally employed in polymer insulating materials like an epoxy resin (EP) to improve the mechanical, thermal, and sometimes even the electrical properties. To understand the influence of filler on the electrical properties of EP/nano-sized titanium oxide (nTiO
₂
) nanocomposites, treeing breakdown tests were performed. The breakdown voltage of the EP/nTiO
₂
nanocomposite with a 1-vol% nTiO
₂
content was higher than that of the EP at the same electrode distance. The nTiO
₂
might capture electrons, leading to an electron avalanche. The improvement effect by adding the nTiO
₂
was also observed in the nanocomposite-mica sheet multi-insulation system. The addition of an appropriate amount of nTiO
₂
to EP may suppress tree initiation and/or tree propagation.