Abstract. Polymer matrix-TiO2 composites were prepared in three different filler concentrations. The electrical relaxation dynamics as well as the electrical conductivity of all samples were examined by means of Broadband Dielectric Spectroscopy (BDS) over a wide frequency and temperature range. The recorded relaxation response includes contributions from both the polymer matrix and the reinforcing phase. Two relaxation modes (β and γ) are observed in the low temperature region, which are attributed to the re-orientation of polar side groups of the matrix and rearrangement of small parts of the polymeric chain respectively. The α-relaxation and the Maxwell-Wagner-Sillars effect (MWS), attributed to the glassrubber transition of the polymeric matrix and to interfacial polarization phenomena respectively, are observed in the high temperature region. These two mechanisms are superimposed, thus a computer simulation procedure was followed in order to distinguish them. MWS effect becomes more pronounced with increasing concentration of the filler following an Arrhenius behaviour. The relaxation frequencies corresponding to α-mode follow the Vogel-Tamann-Fulcher (VTF) equation. An additional relaxation mode is recorded at relatively high temperatures and high frequencies. Its occurrence and dynamics are related to the presence and the concentration of the filler. Finally, the Direct Current (DC) conductivity follows the VTF equation.

Polymer matrix‐ZnO microcomposites were prepared in different filler concentrations. The electrical relaxation dynamics of all samples was examined by means of broadband dielectric spectroscopy (BDS) over a wide temperature range. Two relaxation modes (namely β and γ), observed in the low temperature region, are attributed to the reorientation of small polar groups of the polymer matrix. Glass‐rubber transition (α‐mode) of the polymeric matrix and interfacial polarization phenomena are considered as responsible for the recorded relaxation processes in the high temperature region. An additional relaxation mode, named intermediate dipolar effect (IDE), is recorded at temperatures higher than −30 °C in all composites. Its occurrence and dynamics are related to the presence and concentration of the filler. IDE and α‐relaxation are observed in the same frequency and temperature range, leading to a mutual superposition. The two processes were distinguished following a simulation procedure employing the simultaneous fitting of two Havrilliak‐Negami terms and a third term describing the contribution of DC conductivity to dielectric losses. The temperature dependence of relaxation times for α‐mode follows the Vogel‐Tamann‐Fulcher equation, whereas IDE relaxation times follow unusual temperature dependence. The latter is discussed under the assumption of intrinsic interfacial polarization phenomena within ZnO crystal domains. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 445–454, 2009