Preparation and characteristic evaluation of hydrophobic epoxy-based nanocomposites

Nanocomposite techniques are used to improve the electrical properties of epoxy materials, for example, insulation breakdown strength and partial discharge resistance. In the first step, we prepared epoxy-based nanocomposites by using hydrophobic epoxy as the base resin and 10wt% of titanium dioxide or 5wt% of layered silicate as nano fillers, and measured the partial discharge resistance and insulation breakdown strength. It was confirmed that the depth of the hole caused by partial discharge exposure was decreased to half and one-fourth and the insulation breakdown strength was increased by about 0.8% and 4% with the addition of titanium dioxide or layered silicate, respectively, as compared to the base resin. In the second step, we fabricated impregnated mica tapes, which have been widely used in high-voltage equipment, using nanocomposite epoxy as binder resins. We can see that, although the erosion depth was not changed significantly, the insulation breakdown strength was increased by about 35% and 8.7% in mica tapes containing titanium and layered silicate, respectively, compared with mica tape without nano-fillers.