Effect of maleic anhydride grafted polypropylene compatibilizer on the morphology and properties of polypropylene/multiwalled carbon nanotube composite

The effect of maleic anhydride grafted polypropylene (MA-g-PP) compatibilizer on the mechanical and electrical properties of a polypropylene-carbon nanotube composite is presented. Commercially available grades of polypropylene homopolymer (PP) and multiwalled CNT (MCNT) were used to prepare composites (PP/MCNT) by melt compounding. The effects of maleic anhydride graft level and loading on material properties were investigated. The addition of MCNT without compatibilizer enhanced the mechanical properties of PP, whereas addition of both grades of MA-g-PP alone had a detrimental effect. When MA-g-PP was added as a compatiblizer to the PP/MCNT composite, flexural and tensile moduli increased, indicating that enhanced levels of MCNT dispersion within PP had been achieved. Strength of the nanocomposite decreased with the addition of both grades of MA-g-PP, possibly due to the deterioration of the mechanical properties of the polymer in the presence of lower molecular weight MA-g-PP. Electrical resistivity improved with both grades of MA-g-PP, with higher maleic anhydride graft levels having the most significant effect. Scanning electron microscopy analysis confirmed that the optimum state of dispersion was for the nanocomposite prepared with MA-g-PP with highest grafting level. POLYM. COMPOS., 2012. (c) 2012 Society of Plastics Engineers