Effects of aqueous extraction on the performance and properties of polypropylene/wood composites from Phoenix dactylifera and Acacia tortilis wood

Polypropylene/wood composites were prepared by melt blending technique using a twin screw extruder and subsequently ASTM samples were also prepared by injection molding technique. Untreated and pre-treated particles of Phoenix dactylifera and Acacia tortilis woods are used in this study to investigate the effect of pre-treatments on the different properties of polypropylene/wood composites. The tensile strength of the wood composites was evaluated by ASTMD-638 method and it was found to be higher than the neat polypropylene. The effect of incorporation of wood particles on the melting temperature (T-m), crystallization temperature (T-c) and relative crystallinity (X-c) was also studied and reported. The viscoelastic properties of the PP/wood composites were evaluated. The temperature sweep experiments reveals that the composites storage modulus (G') has higher values than the neat polypropylene at elevated temperature. The water uptake test showed that the composite samples have improved water repletion properties. Water uptake of untreated PP/date palm composites increased from 0.042% after 2 h to 0.12% after 120 h of immersion time. Pre-treated date palm reduced water uptake to 0.077% after 120 h of immersion time. Similar trend was also observed for the composites prepared from A. tortilis wood. The interaction between the wood and the polymer matrix was characterized by Fourier transform infrared spectroscopy technique. The interfacial and the distribution of the wood particles in the polymer matrix were also investigated by scanning electron microscopy.