High Temperature Thermoplastic Composites Utilising Functionalised Multiwall Carbon Nanotube Reinforcement

Carbon nanotubes are the stiffest materials known to man, with a Young’s modulus of ~1TPa. Their use in structural composites is the subject of a concerted international research effort. However, well documented issues related to dispersion and interfacial bonding, combined with their high costs, have limited the commercial exploitation of these materials.The majority of the research effort to date has focused on commodity polymers such as polyolefins, polyamides and polycarbonates. In contrast this study describes the CNT reinforcement of high operating temperature engineering thermoplastics of the sulfone group (namely, polysulfone, polyethersulfone and polyphenylsulfone). These novel nanocomposites, offer the promise of enhanced tensile and impact performance combined with increased operating temperature, fire retardency and electrical conductivity.This study investigates of a range of CNT functionalisation (including acid treatment, surfactants and ODA grafting), and discusses the match between functionalisation and solvent type necessary in order to achieve a stable suspension in a range of solvents. The paper then assesses CNT/poylsulfone composites produced using a solvent casting method in terms of their mechanical properties, CNT distribution, percolation threshold and thermal degradation.