Abstract
Wood particle-polypropylene composites were prepared and the effect of wood particle size on mechanical properties was investigated. The target of this study was micro-order wood particles which reside in transition area from industrial wood composites to nano cellulose composites. Wood particles were fabricated from thinned wood such as cedars and cypresses through ball mill wet crushing. The average size of wood particles, which was controlled by changing the crushing time, was set to three different levels, 30 μm, 50 μm and 150 μm. Then their wood particles were kneaded with polypropylene at the condition that the weight fraction of wood was 10% and maleic anhydride grafted polypropylene (MAPP) was employed for sufficient interfacial adhesion. The specimens were prepared through injection molding and the uni-axial tensile and three-point bending tests were performed. The experimental results indicated elastic modulus and strength decrease almost linearly in both tests as the particle size becomes smaller. This phenomenon was discussed at the view point of crystallinity of matrix polymer to understand the mechanism of wood particle size dependence.
