Physical and Mechanical Properties of WPC Board from Sengon Sawdust and Recycled HDPE Plastic

Wood Plastic Composite (WPC) is a composite material made from sawdust and plastic as polymer bonding, that used in a variety of structural and non-structural applications. Nowadays, In Indonesia WPC is made from Sengon sawdust and recycled HDPE plastic. This research was conducted in order to investigate the physical and mechanical properties of WPC from Sengon sawdust in accordance with ASTM D7031. From the physical test, due to its water restrains, WPC has low moisture content, water absorption and swelling. For the mechanical properties, the bending strength and shear strength are around 40.49 MPa and 27.35 MPa, respectively. However, the WPC tensile strength is lower than common tropical wood, which is only 5.54 to 12.75 MPa, due to the absence of grain in WPC. Furthermore, the modulus of elasticity is only 2113 to 3398 MPa or around one tenth of that wood or concrete modulus of elasticity. From the withdrawal test shows that sheet metal screw type has the highest withdrawal strength compared to cut thread wood, and fine thread drywall screw. Hence, for structural application it is suggested that the WPC board is used for structural element with high moment inertia such as shear wall as its lower modulus of elasticity but has high shear strength.