Studies on crystallization kinetics, microstructure and mechanical properties of different short carbon fiber reinforced polypropylene (SCF/PP) composites

Carbon fiber reinforced thermoplastics provide light weight materials with high mechanical, electrical and thermal properties required for aircraft, automobile and fuel cell and other high-end applications. In this study, short carbon fibers (SCF) of varying length were incorporated into polypropylene (PP) matrix to obtain short carbon fiber reinforced polypropylene (SCF/PP) composites by melt blending and injection molding techniques. The thermo-mechanical properties of SCF/PP composites were studied to investigate the effect of fiber length on their functionality. The crystallization behavior and the microstructure of SCF/PP were studied using several techniques such as differential scanning calorimeter (DSC), rheology and scanning electron microscopy (SEM). The thermo-mechanical stability of SCF/PP composites was shown to be improved with increase in fiber length. The isothermal crystallization kinetics of neat PP and SCF/PP composites were studied using Avrami equation. The results suggested the formation of two-dimensional growth of crystallites from instantaneous nucleation for neat PP as well as SCF/PP composites.