Fabrication and Characterization of High-density Polyethylene - Coconut Coir Composites with Stearic Acid as Compatibilizer

Composites of high-density polyethylene (HDPE) with coconut coir as the fiber and stearic acid (SA) as the coupling agent were fabricated by compression molding. Coconut coir in the form of braided fibers and whiskers were used for the study. Incorporation of the coir, buckled the composites and decreased their tensile strength and elongation at break. The extent of buckling and deterioration in the mechanical properties was proportional to the amount of coir loaded as filler. Treatment of the coir with SA as the coupling agent enhanced the mechanical properties and the thermal stability of the composites. It also reduced the extent of buckling and prevented aging of the composites to certain extent in aqueous and strong acidic and alkaline media. Scanning electron micrographs of the fractured samples showed improved adhesion between coir and HDPE matrix upon treatment with SA.