The purpose of this study is to apply bamboo fibers and powders to resin matrix composites, in order to reduce use of glass fibers which are often pointed out from the viewpoint of environmental impact. Injection molding method was used for fabrication of the composites. The result showed that relatively long short-fibers are not adequate in filling injection molding die, while compounds using small length of short-fibers can fill it well. Especially bamboo powders can be included up to 50wt% in the composite. Alkali-treated bamboo powders are quite useful in increasing the tensile strength of a biodegradable resin matrix composite in comparison with untreated bamboo powders, while the former powders are not so effective in increasing the tensile strength of a polypropylene matrix composite. The biodegradable resin matrix composite including 50wt% bamboo powders is clearly higher in strength than the biodegradable resin matrix composite including 20wt% fibers and the polypropylene matrix composite including 1Owt% fibers.
