Analysis of Creep Properties and Factors Affecting Wood Plastic Composites

Wood plastic composite (WPC) materials are mainly used as building slabs and load-bearing slabs, which will cause creep deformation, structural failure, and safety problems. Therefore, this work used high-density polyethylene and poplar wood flour as the main raw materials to prepare wood–plastic boards. The bending creep tests of wood–plastic sheets were carried out using an orthogonal test method. According to the creep test results, the influences of the WPC ratio molding temperature, pelleting temperature, coupling agent screw speed, and other technological factors on the creep properties of WPC composites under different loads are analyzed, and the influences of WPC creep properties on structural reliability are also analyzed. The results indicate that the wood–plastic ratio and screw speed are significant factors when the load is at 30% bending strength within the 24h creep test. When the load is at 50% bending strength, the wood–plastic ratio and molding temperature are the significant factors. When the load is at 70% bending strength, the wood–plastic ratio is the most significant factor. When the load is at 50% bending strength within the 240 h creep test, the wood–plastic ratio and molding temperature are significant factors. When the load is at 30% bending strength, the influence of each factor on the creeping variable is provided in the following descending order: wood–plastic ratio, molding temperature, granulation temperature, coupling agent, and screw speed, but none of them are significant factors.