Effect of MAPP as coupling agent on the performance of sisal-PP composites

Hybrid composites consisting of polypropylene (PP) and short sisal fibers were prepared by melt mixing followed by compression molding. Various types of chemical treatments such as alkali treatment, cyanoethylation, coupling agent treatment etc. were performed to improve the interfacial adhesion between the fibers and PP matrix. Variations in fiber loading, fiber length, coupling agent concentration and its treatment time period as a function of mechanical strength were studied. The morphology of the interface region was investigated through SEM analysis. Mechanical tests showed that the composites treated with MAPP of grade HCS exhibited optimum strength. Nearly 50% increase in tensile, 30% in flexural and 58% increase in impact strengths were obtained in the case of composites treated with 1% MAPP concentration. Accelerated weathering and water absorption behavior of the MAPP-treated composites further confirmed an efficient fiber-matrix adhesion. Thermal measurements through DSC were also investigated to corroborate the findings of the mechanical data.