Preparation and characterisation of kenaf bast fibre reinforced recycled polypropylene/recycled polyamide 6 composites

Abstract

The purpose of this study was to investigate the effects of kenaf bast fibre (KBF) reinforced recycled polypropylene (rPP)/recycled polyamide 6 (rPA6) composites on mechanical, morphological, thermal and rheological properties. KBF was treated with alkaline treatment and then rPP and rPA6 were prepared by extruding using single screw extruder. Alkaline treated KBF was then reinforced with rPP/rPA6/ maleic anhydride grafted polypropylene (MAPP) blends and the mechanical, morphological, thermal and rheological properties were analysed. The amount of MAPP was fixed at 5 wt. % for all rPP/rPA6 blends. The blends ratios for rPP/rPA6/MAPP were 65/30/5, 45/50/5 and 25/70/5. The best mechanical properties of rPP/rPA6/MAPP blends ratios (25/70/5) then added with various amount of KBF compositions from 0 to 30 parts per hundred resin (phr). The addition of KBF caused the flexural strength and flexural modulus increased proportionally with increasing in its compositions in the composites. The tensile strength, Young’s modulus, and hardness of composites remain unaffected with the increase in KBF composition. However, the elongation at break and impact strength of composites decreased with the increased in KBF compositions. From scanning electron microscope (SEM) micrograph, it was observed that the increase in the KBF compositions caused better dispersion, less interfacial gaps and void spaces. The melting temperature (Tm), crystallization temperature (Tc), degradation temperature (Tdeg), and onset temperature (Tonset) decreased with the increase in KBF compositions in the composites. The melt flow index and rheological properties decreased with the increasing of KBF compositions in the composites. As for conclusion, KBF successfully functioned as reinforcement for rPP/rPA6/MAPP composites