Mechanical properties of wood polymer composites made of sawdust waste and recycled high density polyethylene

This work investigated the mechanical properties of wood polymer composites (WPCs), which were made using recycled high density polyethylene (HDPE) and sawdust waste. Degraded HDPE was used as a coupling agent. Different blends of virgin (vPE) and recycled (rPE) poly ethylene's with various ratio (100/0, 75/25, 50/50, 25/75 and 0/100) were prepared in order to be used as matrices. PE blends and composites were prepared by melt-mixing technique using mini twin-extruder. Mechanical properties such as ultimate tensile strength (UTS), impact strength and Shore hardness were determined for vPE, rPE, PE blends and PE composites. The mechanical properties of PE blends and composites were mainly depended on the composition of its matrices. Presences of degraded HDPE as a coupling agent played an important role on the mechanical properties of WPCs. Increasing the rPE content in the blend composition displayed decrease in the UTS and impact strength properties. The incorporation of only sawdust into vPE, rPE and PE blends matrices caused reduction in UTS and impact strength properties and an increase in Shore hardness. UTS, impact strength and Shore hardness for all WPCs were improved when 5% degraded PE was added. UTS and Shore hardness for composites with 5% degraded PE were higher than that of its matrices. The properties of PE composites were better than that of PE blends, which suggesting that using rPE to attain blends with vPE and then making composites appears to be more preferable than making only PE blends.