Oil palm fiber reinforced polypropylene composites: effects of fiber loading and coupling agents on mechanical,thermal,and interfacial properties

This study investigates the effects of fiber type, fiber loading, and coupling agent on the performance of oil palm biomass (OPB) fiber composites. Fiber composition and fiber morphology were evaluated by scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDAX). Grinded fiber was compounded into polypropylene by means of a twin-screw compounder. Maleated polypropylene (MAPP) was used as a coupling agent during compounding. The incorporated fiber contents for OPB composites were up to 40% (by weight). The compounded samples were prepared into test specimens by injection moulder. The composites were characterized by tensile testing, flexural testing, impact testing, melt flow index, SEM, thermogravimetric analysis (TGA), and differential scanning calorimeter (DSC). The most significant effect on strength and modulus were found by the addition of coupling agent. This was attributed to the thermodynamic segregation of the MAPP toward the interface, resulting in the formation of covalent bonding to the –OH groups of the fiber surface. Composites with MAPP also provided better thermal stability.