Preparation And Properties Of PET Fiber Reinforced Wood Flour/HDPE Composites

This work studies the effects of short cut polyethylene terephthalate (PET) fiber on the properties of wood flour/HDPE composites (PWPC) prepared by extrusion molding process. The dosage, length, shape and distribution of PET fiber on the properties of WPC are investigated by mechanical property, water absorption test and SEM. The suitable amount and length of PET fiber are selected. At the same time, comparing the performance of composite material with the PET fibers and wood powder premixed preparation, PET fiber and thermoplastic matrix of HDPE premixed preparation, as well as open mill and twin screw extrusion molding, respectively. The optimized processing parameters are determined accordingly.Using dispersant scattered the fiber was the optimum, which made the materials gain better mechanical property, but the water resistance of PWPC decreased. Adding PET fiber can improve the mechanical properties of HDPE/wood powder composite materials and water resistance. The appropriate PET fiber amount is within9%.Short cut PET fiber reinforced PWPCs are prepared by open mill and extrusion molding process. The results indicate that the incorporation of PET fiber with the length of2mm had no enhancement on the mechanical properties of wood flour/HDPE composite. With the increasing dosage and length of the PET fiber, the mechanical properties of PWPCs improve slightly. The PWPCs contained6wt%and4mm length PET fiber are obtained the best mechanical properties in the test, which flexural and impact properties improve5%and6%, respectively. The31days cold water absorption and2hours boiling water uptake decrease26.4%and23.4%simultaneously.The impact strength of short cut PET fiber reinforced PWPC which was prepared by double screw extrusion and extrusion molding processthe increases obviously. The highest reaches15.16KJ/m2, increasing27.8%. With the increasing dosage and length of the PET fiber, the mechanical properties of PWPCs improved slightly. At the same time, the water uptake declined rapidly. The longer the fiber length and the more fiber additive amount is, the fewer the water absorption rate is.The results of five different kinds of preparation methods on the performance of wood-plastic composites show that those prepared by double screw extrusion have the better comprehensive mechanical properties, especially the impact strength increases obviously, although the water resistance of PWPCs decreases slightly. The preparation process is relatively simple, saving time and effort, and ultimately it can realize continuous production. During the experiments, the comprehensive mechanics performance of PWPCs which got by open mill and twin-screw extrusion preparation slightly below those by dispersant, which decreased due to the fiber fractured and the degradation of the plastics with multiple mixed.Short cut PET fiber added into wood-plastic composites, which was prepared by twin screw extrusion molding process, could be achieved to improve its mechanical properties, ameliorating the shortcomings of impact strength about WPC. The optimum PET fiber content is between6%and9%, as well as the length is from4mm to6mm.