FATIGUE BEHAVIOR OF WOOD FILLED POLYPROPYLENE COMPOSITE MATERIALS

Current issues on composite materials have been discussed and published in many literatures, including some virtuous inventions on improvement of mechanical properties and hybridizing conventional composites with bio-based fillers. This work includes the development of woods as reinforcing fillers for polymeric matrix to form an environmentally friendly composite material, i.e. wood-plastic composites (WPCs). Appropriate amount of fillers and the compatibility of woods with the hydrophobic polymer are among the issues that have been discussed as the significant factors for improving the properties of the WPCs material. Thus, in this study, different amount of wood fillers was employed to wood-polypropylene (PP) composites in order to clarify the relation between the amount of fillers and the fatigue properties of the WPCs material. Here, the dried WPCs pellets containing relatively higher amount of wood fillers than the polymer matrix were mixed with the dried PP pellets through an extrusion process and molded by the injection molding machine. From the tensile test results, it was understood that the tensile properties of the plain PP was proportionally enhanced by increasing the weight fraction of the wood fillers. A similar result was obtained from fatigue test, which suggested that the increase in weight fraction of woods enhanced the fatigue properties of the WPCs material. The improvement of both properties was estimated due to the good interfacial adhesion of matrix-fillers which was assisted by the addition of the coupling agent. Further analysis on fracture surface has been carried out and the relation between microscopic fracture and the fatigue behavior will be further discussed in this study.