Reinforcement of poly(vinyl chloride) and polystyrene using chlorinated polypropylene grafted carbon nanotubes

Multiwalled carbon nanotubes, covalently functionalised with chlorinated polypropylene, were used as the filler material in polymer nanotube composites. Both polystyrene and poly(vinyl chloride) were used as the polymer matrix. The functionalised nanotubes could be stably dispersed in tetrahydrofuran allowing the preparation of composites by solution processing. Close to a twofold increase in both modulus and strength were measured at nanotube loading levels of less than 1 vol%. Reinforcement values of dY/dVf = 115 ± 34 GPa and dY/dVf = 304 ± 90 GPa were observed for polystyrene and poly(vinyl chloride) based composites respectively. The high levels of reinforcement are due to the superior dispersion and stress transfer as evidenced by SEM images of the fracture surfaces. These properties can both be attributed to the presence of the functional groups.