Chapter 9 - Electrical conductivity of short fibre-reinforced polymers

Abstract

Engineering materials applied in electrical and electronic devices must possess electrical conductivity (EC). Although short fibre-reinforced polymer (SFRP) composites have been widely used in these applications, most polymers are nonconductive. Substantial enhancement in EC can be achieved by incorporating small amounts of conducting fillers such as short carbon fibres into nonconductive polymers. Other conducting fillers that can be simultaneously incorporated into polymers include carbon black, carbon nanotubes and metal particles. Our discussion of the EC of SFRP composites in this chapter considers the percolation threshold, the effects of conducting short-fibre content and aspect ratio as well as the synergistic effect of the hybridisation of short fibres with other shaped or nanosized conducting fillers. First, the percolation threshold resulting from electrically percolated inclusions, which is a special feature of conducting SFRP composites, is introduced and discussed. Second, the EC of the SFRP composites is shown to be related to the conducting short-fibre content and aspect ratio. In general, an increase in both will lead to an increase in the composite EC. Moreover, we can see that the hybridisation of conducting short fibres with other shaped or nanosized conducting fillers brings about possible superior EC for hybrid composites over single short-fibre composites.