Physical and mechanical properties of wood-plastic composite made of Canola stem residues and polypropylene

In this study, physical and mechanical properties of wood-plastic composite made of Canola stem flour and polypropylene were investigated. Variable factors were four levels of canola stem flour (25, 50, 75 and 100 percent based on the dry weight of the wood flour) with and without pit. The control samples were made of only wood flour and polypropylene. Physical and mechanical properties including screw withdrawal strength perpendicular on the surface, flexural strength, modulus of elasticity, water absorption and thickness swelling after 2 and 24 hours immersion in water were measured in accordance with EN standards. Results showed that increasing the mixing ratio of canola stem flour to wood flour up to 25% resulted in increase in screw withdrawal strength perpendicular to the surface. Increasing this factor up to 50% led to increase in MOR and MOE. Thereafter, any increase in the mixture, decreased mechanical strengths. Increasing the mixing ratio of canola stem flour to wood flour resulted in increase in water absorption and thickness swelling after 2 and 24 hrs. The specimens without pit showed lowest amount of water absorption and thickness swelling levels and highest mechanical properties (screw withdrawal resistance, flexural strength and modulus of elasticity).