Modelling of dielectric relaxation processes of epoxy-resin filled with carbon black particles

Composites of an epoxy-resin matrix with randomly dispersed carbon black nanoparticles in various amounts and below the percolation threshold were prepared and their dielectric spectra were measured in the frequency range from 100 Hz to 20 MHz and temperature range from 20 °C to 95 °C. The obtained data were analyzed by means of electric permittivity formalism. Two dielectric relaxation processes were revealed in the frequency range and temperature interval of the measurements. One of these relaxations appearing near the glass transition temperature was associated with the interfacial polarization effect. Whereas the other appearing at lower temperature is consistent with the Havriliak-Negami model. Furthermore, the analysis of the temperature dependence of their relaxation time using the Vogel-Tammam-Fulcher (VTF) model shows the existence of carbon black/matrix interaction.