Mechanical and water kinetic parameters of water-absorbed hard wood dust/high-density polyethylene composites

Abstract

The mechanical (flexural, tensile and impact) properties and water kinetic parameters of water-absorbed hard wood (mangrove) reinforced high-density polyethylene composites were evaluated as untreated and treated mangrove dust (MD). Samples were prepared by mixing high-density polyethylene (HDPE) with MD at 10, 20 and 30% by weight in a twin-screw laboratory compounder and injection moulded into dumb-bell and rectangular-shaped test specimens for flexural, tensile and impact tests. Samples were soaked in distilled water for 1440 h at room temperature and a relative humidity of ~ 65%. The flexural strength and modulus indicated that treated composites exhibited lower decrease in values than their untreated counterparts at water equilibrium points. The dry composites maintained higher values of tensile properties, notwithstanding the treatment. Scanning electron microscopy of impact fractured surfaces showed evidence of improved MD-HDPE interfacial adhesion of treated composites in both dry and water-absorbed conditions. The water kinetics parameters such as the diffusion, sorption and permeability coefficients further show that dry composites are more water-resistant than the wet composites. Overall, the treated composites at dry and moisture-saturated conditions indicated better mechanical and moisture stability than the untreated MD/HDPE composites.