Dielectric Properties of Epoxy/Alumina Nanocomposite Influenced by Particle Dispersibility

For applications of nanocomposite materials to solid insulator for electric power apparatus, we have to consider various characteristics from mechanical, thermal and electrical points of view. In particular, the agglomerate of nanoparticles would decline the excellent properties of nanocomposite. In this paper, we investigated the influence of dispersibility of nanoparticles on electrical properties. Firstly, we fabricated epoxy/alumina nanocomposites with application of ultrasonic wave and centrifugal force. Secondly, we evaluated the dispersibility of nanoparticles by image analysis of agglomerate diameter from scanning electron microscopy (SEM) and the measurement of filler contents. Then, we examined the dielectric properties such as permittivity and dielectric loss of the nanocomposite. Finally, we verified the influence of the dispersibility of nanoparticles on the dielectric characteristics.