木質フィラーを用いたプラスチック複合材料の機械的特性評価

Abstract

The purpose of this study is to investigate the effect of wood particle size on mechanical properties of wood plastic composites (WPC). The target of this study was wood flour of 100 μm or less. Wood chips which were manufactured from cedars and cypresses were employed as the feedstocks. Wood flour was finally prepared by wet milling. Then the average size of wood flour was adjusted to three types (approximately 30 μm, 60 μm and 140 μm) by changing the milling time. Their wood flour was kneaded with polypropylene and maleic anhydride grafted polypropylene (MAPP). Then weight fraction of wood flour and MAPP was 10%. The tensile test specimens were prepared by injection molding. Mechanical properties of the composites were evaluated with the uni-axial tensile test. The results indicated that elastic modulus and strength decrease as the wood particle size becomes smaller. We employed multiscale finite element method based on homogenization in order to understand the influence of microstructural factors on elastic modulus of the WPC. The computation indicated that the wood particle size dependence of elastic modulus is caused by mechanical property change of matrix.