Improvement in the mechanical performance and interfacial behavior of kenaf fiber reinforced high density polyethylene composites by the addition of maleic anhydride grafted high density polyethylene

The effects of compatibilizer on the tensile, flexural and interfacial adhesion behavior of kenaf fiber reinforced high density polyethylene composites were investigated. The addition of maleic anhydride grafted high density polyethylene (MA-HDPE) as compatibilizer into the composites was found to improve the mechanical properties and the adhesion behavior of the composites. These improvements were due to the improved compatibility between matrix and fiber. 8 % MA-HDPE loading provided maximum enhancement in tensile and flexural properties when compared to the other compatibilizer contents. Meanwhile, uncompatibilized composites showed poorer mechanical properties and interfacial behavior relative to the compatibilized composites. Fourier transformed infrared spectroscopy analysis confirmed the changed chemical structures by the appearance of stretching vibration of the ester carbonyl groups (C = O) around 1725 cm⁻¹ to 1742 cm⁻¹ and the peak of hydroxyl group at 3327 cm⁻¹ in the compatibilized composites. This indicates that the maleic anhydride has bonded to the kenaf fiber through esterification reaction, giving rise to strong interfacial bonding between the matrix and fiber. The improvement in the interfacial behavior was evident from the tensile fracture surface morphology using a field emission scanning electron microscopy.