AC Breakdown Strength and Volume Resistivity Characteristics of Epoxy Resin Composite with Surface Modified Alumina Nanoparticles

Surface modification is an efficient approach to improve the dispersion of alumina nanoparticles. In addition, it is also useful for improving the electrical properties of polymer nanocomposites. In this work, alumina nanoparticles were treated by the saline coupling agent of γ-Aminopropyltriethoxysilane (KH550) to restrict the aggregation. The chemical bonding was examined by Fourier Transform Infrared Spectroscopy (FTIR). Experiment results confirmed that the chemical bond was formed between alumina and KH550 after modification. The modified epoxy/alumina has more traps which results in larger volume resistivity which is 2.22×10
¹⁷
Ω/cm when the alumina content is 1wt%. With increase of the filler concentration, e.g. 3 and 5 wt%, many over lapping interaction zones occur so that the effect of deep traps is gradually weakened and the effect of shallow traps is increased which resulting the decreased volume resistivity. The modified alumina/epoxy resin nanocomposite shows a higher AC breakdown strength as compare to unmodified nanocomposites.