Dielectric relaxation in particle-filled polymer: Influence of the filler particles and thermal treatments

Abstract

Variable-temperature measurements of the frequency-dependent complex effective permittivity are performed on silicon dioxide loaded epoxy resin composites. Two relaxation peaks due to conductivity and α-relaxation processes are identified. The amplitude and relaxation frequency of each peak strongly vary according to filler and material treatments while the activation energy of the Arrhenius ionic conductivity remains unchanged. These trends are compared to previous works. We argue that the changes in amplitude and relaxation frequency can be attributed to ions trapped in silicon dioxide particles and to a significant change in the elasticity network of the polymer chains.