Correlation of free space length and surface energy of epoxy nanocomposites to surface tracking

Glass-fiber reinforced epoxy nanocomposites are widely used in high voltage outdoor applications. One of the serious problems of outdoor insulation is the surface tracking and erosion that leads to premature failure of insulation. In this paper free-space length, surface energy and surface tracking of epoxy composites with nano alumina, silica and micro alumina trihydrate fillers and unidirectional glass fiber reinforcement are discussed. Quantitative interfacial analysis has been used by determining the freespace length of the composites. The results of tracking are explained on the basis of contact angle measurements and the concept of surface energy is used to substantiate the results. The time-to-track and surface erosion of dry and water treated nanocomposites are determined by the inclined plane tracking and erosion method. The experimental results have revealed that the hydrophobic nature of glass epoxy composites improves with addition of fillers. The surface energy, wettability and interaction parameters show reduction with the addition of fillers. It is observed that the Glass Epoxy composite with combination of nano alumina, silica and micro ATH fillers exhibits good thermal, electrical and mechanical properties with improved tracking and erosion resistance.