An experimental and theoretical study on the electrical conductivity of polymer composites

In recent years, hydrogen fuel cells have emerged as one of the most promising green energy sources. Although they and their manufacturing technology are still under development, recent research has shown encouraging progress. While polymers are typically known for their excellent electrical insulating properties, incorporating appropriate conductive fillers can transform them into electrically conductive composites. Potential fillers include graphite, graphene, carbon black, and carbon fibers. In this study, we evaluate the effect of the properties of fillers on mechanical properties, and thermal and electrical conductivity in conductive mono-composites. Our results and conclusions can contribute to the development of conductive hybrid polymer composites suitable for fuel cell applications. We prepared composites using carbon black, carbon fiber, and graphite in a polypropylene matrix. We investigated the effects of processing parameters and evaluated the resulting materials' mechanical, thermal, and electrical properties. Among the tested fillers, one type of graphite exhibited superior electrical and thermal conductivity without compromising mechanical performance. Furthermore, we adapted a semi-empirical thermal conductivity model to describe the electrical conductivity of composites above the percolation threshold. The modified model showed high accuracy, offering a practical tool for material design and engineering applications. • Structure–property link in PP/carbon composites driven by filler morphology • Semi-empirical model accurately predicts conductivity (R 2 > 0.997) above percolation • Graphite flakes give top conductivity but reduce flexural strength significantly • Milled carbon fiber uniquely improves flexural strength in conductive composites