Breakdown Strength of TiO2/Epoxy Nanocomposites Using Centrifugation Agglomerate Removal

In this study, TiO 2 /epoxy nanocomposites are evaluated for impulse and AC breakdown strength when agglomerations of TiO 2 nanofillers are removed by centrifugation. It is found that the nanocomposites with micrometric agglomerates exhibit lower breakdown strengths than that of unfilled epoxy resin. However, with the removal of agglomerates larger than 0.5 µm for 0.4 vol% filler concentration, the breakdown strengths are higher than that of unfilled epoxy resin. Micrometric agglomerates of TiO 2 nanoparticles behave as defects, thus lowering the breakdown strength of the nanocomposites. When such agglomerates are removed prior to curing, an improvement of the breakdown strengths is observed with very low filler concentration.