Chemical, morphological and mechanical analysis of sisal fiber-reinforced recycled high-density polyethylene composites

Abstract

Natural fibers are widely used as plastic composite material reinforcements. In this work, composites of post- consumer high-density polyethylene (HDPE) reinforced with sisal fibers were prepared. PE and sisal fibers were chemi- cally modified to improve their compatibilities, try to increase the hydrophobic character of the sisal fiber and hydrophilic character HDPE. Sisal was mercerized with a NaOH solution and acetylated and the PE was oxidized with KMnO4 solu- tion. The chemically modified fibers were characterized by Fourier Transformed Infrared Spectroscopy (FTIR) and 13 C Nuclear Magnetic Resonance Spectroscopy ( 13 C NMR). The composites were prepared by extrusion of modified and unmodified materials containing either 5 or 10 wt% fibers. The morphology of the obtained materials was evaluated by SEM. The fiber chemical modification improves it adhesion with matrix, but not benefit were obtained with HDPE oxida- tion. Flexural and impact tests demonstrated that the composites prepared with modified sisal fibers and unmodified PE present improved mechanical performance compared to pure PE.