Effect of nano-silica on dielectric properties and space charge behavior of epoxy resin under temperature gradient

Epoxy resin (EP) nanodielectrics with the mass fraction of nano-silica (SiO2) between 0 and 5 wt% were manufactured. The influence of SiO2 content on the dielectric properties of EP nanodielectrics was studied. It is found that the dielectric properties are the best when the SiO2 content is 0.5 wt%. We further tested and analyzed the dielectric properties of pure EP and EP nanodielectrics with 0.5 wt% SiO2 at the temperature ranging from 40 to 200 degrees C. The results show that the complexity permittivity and space charge accumulation of the samples increase significantly at low frequency and the temperature above Tg. The complexity permittivity and space charge accumulation of the nanocomposites with the loading of 0.5 wt%, however, are smaller than that of pure EP. These results indicate that the interface area between nanosilica and EP matrix suppresses the motions of molecular chains and the migration of charge carriers.