High performance PP/SEBS/CNF composites: evaluation of mechanical, thermal degradation, and crystallization properties

Nanocomposites comprising carbon nanofibers (CNF) were prepared and evaluated in terms of morphology, mechanical performance, thermal stability and crystallization properties. It was found that addition of CNF reinforced polypropylene (PP) matrix by marginally increasing the strength and modulus, but at the expense of toughness and ductility. To improve the toughness of the composites, polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) was used. Presence of SEBS remarkably improved the toughness and ductility of the composites. The optimum level of reinforcement was observed at 0.1 wt% of CNF in the composites. Phase morphology studies revealed that at this concentration, CNF were well dispersed in polymer phases and beyond it, agglomeration occurred. PP/SEBS/CNF (0.1 wt%) nanocomposites exhibited good strength, excellent toughness and decent modulus, which make them suitable for cost effective, light-weight, tough and stiff material for engineering applications. It was observed that thermal stability of composites is only marginally improved whereas crystallinity of PP drastically reduced by the addition of CNF.