An investigation on the mechanical properties of the wood plastics composite reinforced with waste polyester fibers

Background and objectives: This study has been undertaken to investigate effects of synthetic waste fibers of polyester in improving mechanical properties of wood plastic composites and also in reducing the accumulation of fiber listed on the environment and reduce environmental pollution through efficient use of raw waste material (polyester fiber) in human needs and in promote WPC industry and improve economic conditions in the industry. Until now, many researchers have studied variety of methods such as modification the surface fiber, use of additives materials and Hybrid to improve the physical and mechanical properties of wood plastic composite. According to researches, one of the applicative resources to improve the properties of wood-plastic composites is synthetic organic materials. Researchers in various scientific disciplines from synthetic organic materials of polymer fiber produced short fibers and have used them in various structures including concrete, asphalt and wood plastic in order to strengthen the physical and mechanical properties them.
Materials and methods: Two types of polyester fibers (carpet fibers and plush fibers), high density polyethylene, wood flour of populus, maleic anhydride grafted polyethylene (MAPE) and ethylene- glycidyl methacrylate copolymer (E-GMA) as coupling agent were used. After two-stage mixing, resulted granules were hot pressed (at160 , under 10 Mpa pressures) to produce test boards measuring 20×20×0.7 cm in dimensions. Then to evaluate the mechanical strength including flexural strength, tensile strength and impact strength, test boards were prepared and were cute according to standard. It should be noted that were taken images by Scanning Electron Microscopy from the tensile fracture surface of composite in order to examine the effect of the polyester fibers (carpet fiber and Plush fiber) on the mechanical properties of wood-plastic composite more closely.
Results: Results from measurement of mechanical properties of the samples have shown that with increasing the amount of polyester fibers (carpet fibers and plush fibers), tensile modulus of elasticity of wood plastic composites decreases and increases his flexural modulus of elasticity. Also by increasing amount carpet fibers, the tensile, flexural and impact strengths of wood plastic composites-carpet fibers increases. Morphologic study by Scanning Electron Microscopy indicates that with the increasing percentage of polyester fibers, is denser and smoother the integration between the fracture surface of the composite material.
Conclusion: The maximum of flexural strength is in a sample that contained 20 wt% carpet fibers. But about the plush fiber, 10 wt% of it is efficient for increasing the flexural and tensile strengths of wood plastic composites-plush fibers.
Keywords: polyester, composite, wood plastic.