Effect of Particle Size and Dispersion on Dielectric Properties in ZnO/Epoxy Resin Composites

In this paper, ZnO-Epoxy nanocomposites (NEP) were prepared and epoxy composites that contain 5 wt% microZnO (MEP) and deliberately not well dispersed nano ZnO (NDNEP) were also prepared for purpose of comparison.The effects of the particle size and dispersion of ZnO on dielectric properties of epoxy resin were chiefly studied.Test results showed that: at a loading of 5 wt%, the three epoxy composites seem to have no significant difference onresistivity compared to epoxy resin; Dielectric constants of all the epoxy composites are also basically the same butthey are bigger compared to that of the pure epoxy resin (unfilled); Dielectric dissipation factors (tanδ) of NDNEP isgreater than that of NEP and MEP. NEP has the minimum dielectric loss factor, whereas dielectric loss factors of thethree epoxy composites are larger than that of the pure epoxy resin. The decreasing order of electrical breakdownstrength for the three epoxy composites and for the pure epoxy resin is as follows: NEP>MEP>NDNEP>EP. Finally,in order to explain the experimental results the aggregation interface phase was proposed. Furthermore, addition ofwell dispersed nano filler has proved to have a positive effect on the improvement of the dielectric properties of epoxyresin.