Electric properties and dielectric spectra of epoxy-based nanocomposites

The characteristic properties of nanocomposite insulating materials can be influenced by the properties of the interfaces between the nanoparticles and the polymer matrix. Assuming that the formation of an interphase would have an impact on both electric and dielectric properties of nanocomposites, the influence of silica and titania particles on electric properties, in particular the resistance to high-voltage, low-current arc discharges, as well as on the dielectric spectra is studied. Depending on type and surface property of the filler particles the arc resistance of the nanocomposites has a characteristic maximum at small filler contents. In particular, for the material composition with the highest resistance to arc the dielectric spectra show a significant change in the frequency dependence of the relaxation processes.