Electrical Properties of Polypropylene-Based Composites Melt-Processed with As-Grown Carbon Nanofibers

Abstract

Electrical conductivity, dielectric permittivity, electrical modulus, and electrical impedance of polypropylene (PP) composites melt-processed with different contents of as-grown carbon nanofibers (CNFs) are studied. As expected, the electrical conductivity of PP/CNF composites increased as the incorporation of CNFs is raised in the polymer, yielding a maximum of ∼ 6 ×10−6 S m−1 for PP/CNF 3 wt. % composites. That enhancement relates to a gradual improvement of the dielectric permittivity as the incorporation of CNFs rises into the PP up to a maximum of ∼ 13 for PP/CNF 3 wt. % composites at 1MHz, which is attributed to the rise of the interface polarization effect. Moreover, the Cole-Cole model is used through the electrical modulus to analyze the effect of CNF contents on the dielectric relaxation of PP/CNF composites from which is deduced that the incorporation of CNFs increases their heterogeneity and relaxation times. The analysis gathered here aims at contributing to the understanding of the electric features of polymer composites filled with a type of CNFs, which are not subjected to any thermal post-processing method after their synthesis by chemical vapor deposition (CVD).