The research on palm kernel shell (PKS) and nanosilica filled polypropylene (PP) hybrid composites consists of four parts. The first part is mainly to investigate the effect of incorporating PKS as single filler on the mechanical, water !lbsorption, morphology and thermal properties ofPP. PKS (10-40 weight% filler loading) was compounded with polypropylene using Brabender Plastograph internal mixer at processing temperature 180°C and rotor speed 50 rpm. Preliminary results show that the tensile strength, impact strength and elongation at break decreased with the increasing of filler loading but increased the tensile modulus and water absorption. The morphology study using scanning electron microscopy (SEM) shows poor interfacial interaction between PKS and PP with the increasing of filler content. In addition, PKS was found to be a poor nucleating agent in thermal studies. The second part of the research is to study the effect of incorporation of nanosilica on mechanical properties of PP. Nanosilica (l-5 weight%) were mixed with PP using internal mixer at processing temperature 180°C and rotor speed 50 rpm. The mechanical properties ofnanosilica filled PP composites were compared to determine the best balance in mechanical properties which would be used as platform for the study of hybrid PP composites in the third part of the research. The results show that at low filler loading the composite exhibit high tensile strength and elongation at break but with the increasing of filler loading, the strength and elongation started to deteriorate. The third part of the research would be to use the strongest nanosilica filled PP composite formulation, i. e. nanosilica filled PP with 2 weight % filler loading, to act as benchmark for the determination of the optimum hybrid composite formulation. Subsequently, all the hybrid composites in the studies were to have 2 weight % of nanosilica loading. The hybrid composites were compounded using similar parameters as in PKS filled PP composites. The usage of two types of filler in PP matrix was found to enhance the tensile strength, elongation at break and impact strength but reduced the tensile modulus and water absorption of the PP composites. Thermal studied confirmed that the improved nucleating ability of the hybrid fillers contributed to the superb mechanical properties of the hybrid composites. The final part involved subjecting the single-filler and hybrid filler PP composites to polypropylene grafted maleic anhydride (PP-g-MA) compatibilizer. The effect of chemical modification of single-filler and hybrid composites with PP-g-MA improved tensile strength, tensile modulus, impact strength and crystallinity but decreased water uptake. The morphology study shows better interaction between filler and matrix with the usage of2 weight% ofPP-g-MA.
