Influence of maleic anhydride compatibiliser on properties of polpropylene/multiwalled carbon nanotube composites

The effect of maleic anhydride compatibilser on the mechanical, rheological and thermal properties of polypropylene–carbon nanotube composites is reported. A commercial grade of polypropylene copolymer was melt compounded with acid purified multiwalled carbon nanotubes at loadings up to 12 wt-%, with and without the addition of a maleic anhydride grafted polypropylene. Tensile and flexural moduli were found to increase with filler content at all nanotube loadings and these properties were enhanced by addition of maleic anhydride. Ultimate tensile strength increased with nanotube loadings up to 8 wt-% and then decreased; maleic anhydride had a negative effect on tensile strength most likely resulting from nanotube agglomerations. Rheological and morphological characterisations confirmed that dispersion was relatively poor in both systems suggesting that maleic anhydride improved interfacial bonding without significantly improving dispersion, for the materials and compounding conditions examined in this work.