Temperature Dependence of Direct Current Conductivity in TiO2/Epoxy Polymer Dielectric Nanocomposites

A study is performed of the effect TiO2 nanoparticles have on the temperature dependence of the direct current conductivity of epoxy polymers. The value of direct current conductivity is determined by analyzing the frequency dependence of the complex permittivity in the 10(2)-10(5) Hz range of frequencies. Two characteristic regions are found on the temperature dependence of direct current conductivity: the Vogel-Fulcher-Tammann dependence above the glass transition temperature (T-g), and the Arrhenius dependence below T-g, due apparently to a change in the mechanism of conduction after the freezing of ionic mobility at temperatures <T-g. It is found the calculated energy of activation of the Arrhenius process changes upon raising the concentration of TiO2 nanoparticles.