Physical and mechanical properties of composites made from bamboo and woody wastes in Taiwan

This study investigated the physical and mechanical properties of six groups of bamboo-wood composites (BWC) made from bamboo and wood wastes, which are produced from the industry processing in Taiwan. Results obtained from non-destructive testing (NDT) indicated that the boards made with 100% bamboo residues (Group B) revealed higher ultrasonic-wave velocity (V-u) and tap tone sound velocity (V-t) than other BWC boards. Both V-u and V-t of composite boards were proportional to the ratio of bamboo residues contains. Three-layer composites made with bamboo/wood/bamboo residues at 1:2:1 ratio (Group B/2W/B) had the highest specific strength as well as modulus of elasticity (MOE) and modulus of rupture (MOR) among all the composites. B/2W/B composite board had structural characteristics similar to those of medium-density fiberboards (MDF) and particleboards; thus, it might have better compression resistance than other types of boards. B/2W/B composite board also had the highest screw holding strength (SHS); next was the boards composed entirely of woody wastes (Group W). The results obtained from analysis of water absorption rate (WA%) show a positive correlation with porous bamboo contents; meanwhile, wood chips have higher water-absorption swelling rate than bamboo residues. Hence, it showed greater change in thickness swelling coefficient (TS%) and volume swelling coefficient (S%).