Influence of surface treatment on the properties of high density polyethylene composites filled with palm kernel shell

Abstract

The high density polyethylene (HDPE) composites filled with palm kernel shell (PKS) were prepared using Z-blade mixer at processing temperature 190 ˚C and rotor speed 30 rpm. The effect of filler loading of PKS on mechanical, morphological and thermal properties were investigated. The mechanical properties of untreated HDPE/PKS composites showed that 30 php of PKS loading has the optimum tensile strength. Meanwhile, the increasing of filler loading have decreased the elongation at break and thermal stability but increased the modulus of elasticity. The morphological studies of untreated HDPE/PKS composites showed poor dispersion of PKS and weak adhesion with HDPE. In order to improve the properties of composites, alkaline treatment was carried out. The alkaline treatment enhanced the tensile strength, elongation at break and thermal stability but decreased the modulus of elasticity and water absorption of HDPE/PKS composites. The morphological studies shows that the surface roughness of the filler increased as the concentration of NaOH increased hence improved the fillermatrix interaction. The fourier transform infrared spectroscopy (FTIR) results reported that the number of hydroxyl groups reduced and part of lignin was also been removed from the filler when alkaline concentration increased.