Electret properties and electrical conductivity of polypropylene-polyphenylene sulfide composites

The electret properties and electrical conductivity of polypropylene-polyphenylene sulfide (PP-PPS) composites were studied. The results reveal that the effective surface charge density is higher in fibrous-porous materials (FPM) compared to film-based composites. In the electrical conductivity-temperature dependence, a characteristic up-turn is observed at a temperature of 110 °C, where the high-temperature segment of the curve corresponds to the intrinsic conductivity of the composite. The low-temperature segment can be attributed to structural defects. Additionally, two relaxation maxima are identified in the thermally stimulated depolarization (TSD) current spectra. The low-temperature peak is associated with the charge relaxation at the matrix-filler interface, a phenomenon driven by Maxwell — Wagner polarization. The high-temperature maxima are likely related to the relaxation of charges governed by the intrinsic conductivity of PP in its amorphous phase.