Rheological and electrical properties of polypropylene composites containing functionalized multi-walled carbon nanotubes and compatibilizers

Multi-walled carbon nanotubes (MWCNTs) were chemically functionalized through acid, amine, and heat treatments. These were used in the manufacture of composites using polypropylene (PP) as matrix and two types of compatibilizers, maleic anhydride grafted polypropylene (MA-g-PP) and maleic anhydride grafted styrene–ethylene/butylene–styrene (MA-g-SEBS). PP/MWCNT composites filled with modified MWCNTs and compatibilizers were prepared by melt compounding with a twin-screw extruder and were evaluated to understand the effect of dispersion and interfacial interaction on the morphological, rheological, and electrical properties of the composite. When heat treated MWCNTs and compatibilizers were added to the composite, three dimensional network structures were generated through nanotube–nanotube and nanotube–matrix interactions resulting in percolation. Electrical conductivity was dramatically increased when the heat treated MWCNTs were added to the composite and was increased further with the addition of MA-g-SEBS compatibilizer.