Effects of particle size and orientation on properties of particleboard made from Ethiopian highland bamboo (Yushania alpina)

This study was conducted to evaluate the effects of particle size and orientation on the properties of particleboards made from Ethiopian highland bamboo (Yushania alpina). Oriented and control boards of 750 kg/m(3) were fabricated from three-year old bamboo using two particle sizes of 1-2 and > 2 nun mesh sizes. Urea formaldehyde resin was used as a binder. Properties of the boards were evaluated based on the ISO Standards for Wood-based Panel Products (2003). The oriented particleboards had 15% and 37% higher modulus of rupture and modulus of elasticity, respectively, compared to the controls. The internal bond (IB) strength of the boards was more affected by particle size than particle alignment. Boards made from small particles recorded 35% higher IB than those made from coarse particles. Screw withdrawal resistance was significantly affected by both particle size and alignment. Boards made from coarse particles boards had 9% and 12% higher edge and surface screw withdrawal resistance, respectively, than those made from small particles. About 8% superior edge and surface screw withdrawal resistance was obtained in randomly oriented boards than parallel-oriented boards. Particle alignment did not show significant effect on the thickness swelling (TS) and water absorption (WA) of oriented boards, whereas particle sizes had significant effects on both tests. Boards made from small particles had 12% and 20% lower TS and WA, respectively, than those made from coarse particles.