Effects of bark content and particle geometry on the physical and mechanical properties of particleboard made from black spruce and trembling aspen bark.

Abstract

Bark residues are mostly used for thermal energy production. However, a better utilization of that resource could be as raw material for particleboard manufacturing. The use of bark in wood particleboard manufacturing is currently viewed negatively due to the fact that an excessive bark content in the furnish produces significant adverse effects on strength properties and dimensional stability of the boards. Strategies could be found to improve some properties of particleboard made from bark. The effects of bark particle content and geometry on the physical and mechanical properties of the panels including the modulus of elasticity (MOE), modulus of rupture (MOR), internal bond (IB), Janka hardness (HJ), thickness swelling (TS), and linear expansion (LE) were investigated. The best panels in terms of properties were compared to a control made of 100 percent wood particles. The results showed that, while the mechanical properties of the particleboard made from black spruce and trembling aspen bark decreased with increasing bark content, LE increased and TS increased slightly. The IB of particleboard made from 50 percent bark content decreased with increasing particle size. Particleboard made from 50 percent black spruce bark showed the highest MOE, MOR, and IB and the lowest LE with values 12, 37, and 54 percent lower and 45 percent higher than the control, respectively. The MOE, MOR, IB, and HJ of boards made from 50 percent black spruce and trembling aspen bark met the requirements of the ANSI A208.1 to 1999 standard. Particleboard made from trembling aspen bark showed the lowest TS.