High-density polyethylene filled with particulate of three local wood species: physical and mechanical properties

In this research, wood from three types of locally grown trees in Saudi Arabia was used to formulate plastic/wood composites. High-density polyethylene (HDPE) served as the matrix for wood powder. Composites were prepared in the molten state using an internal mixer at 250 °C. Wood powder was added to HDPE at 15 wt-%. Thermal and mechanical properties, along with moisture uptake, were investigated. The results showed that these three wood powders increased the tensile strength of composites by 28% to 45% compared with neat HDPE. However, the toughness of composites decreased drastically upon introducing wood into the HDPE matrix. The addition of these three local tree woods lowered the crystallinity of the HDPE/wood composites. The lowest crystallinity was observed with Talh wood. Composites containing Seder wood absorbed less moisture than those with Talh and Samor, as well as neat HDPE. Adding up to 4 wt-% ash to the HDPE/wood composites effectively reduced moisture uptake to as low as 0.16 wt-%.