Dielectric Properties of PMMA/PPy Composite Materials

This work presents a study of the structural, electrical, and dielectric properties of polymethylmethacrylate/polypyrrole composites. Structural analysis was performed using X-ray diffraction, showing an increase in the crystallinity index with the increasing of filler concentrations. The electrical conductivity mechanism and the dielectric relaxation process of these composites were studied in the frequency range from 100 Hz to 1 MHz and temperature range from 290 to 380 K, using impedance spectroscopy. The frequency-dependence of the conductivity is analyzed using the Jonscher power law. The values of the n exponent in this law are superior to 1, which is an indication that electron hopping occurs between neighboring sites. The Nyquist representations of the complex impedance spectra are modeled using the Cole-Cole model. The temperature dependence of both DC conductivity and relaxation process behaviors, using the Arrhenius equation, indicates that the conduction process is thermally activated.