POLYPROPYLENE-KENAF COMPOSITES PREPARED FROM DIFFERENT COMPOUNDINGTECHNIQUES

摘要

A comparison study was carried out to determine the effect of different types of compounding techniques, i.e. internal mixer, twin screw extruder and high speed mixer in the preparation of polypropylene-kenaf composite. The effect of percentage kenaf(core) loading (20%, 40%, 60%) on the tensile and impact properties of the composite were investigated. From the results, the addition of kenaf, regardless of particle size had resulted in the reduction of tensile and impact strength of the composite. Itwas due to poor interfacial bonding between kenaf (hydrophilic) and polypropylene (hydrophobic). In addition, a reduction in impact strength of the composite was due to the stiffness of the composite and kenaf particle agglomeration, which facilitated crack propagation. However, tensile modulus of the composites increased as the percentage of kenaf loading was increased. As a comparison, composites produced from internal mixer had displayed higher tensile and impact properties as compared to those prepared from high speed mixer and twin screw extruder. It was believed that this phenomenon was attributed to the effectiveness of internal mixer with a better compounding mechanism which improved the wetting and distribution on kenaf within the polypropylene matrix.