Physical and mechanical properties of particleboard made from extracted black spruce and trembling aspen bark

Bark residues are mostly used for thermal energy production. However, a better utilization of that resource could be as raw material for particleboard (PB) manufacturing. Bark is also a source of numerous extractives used in several fields including pharmacology and adhesive production. This study aims at analyzing the effect of hot water extracted bark particle content and size on the physical and mechanical properties of bark PBs including the modulus of elasticity (MOE), modulus of rupture (MOR), internal bond (IB). Janka hardness (HJ), thickness swelling (TS) and linear expansion (LE). Moreover, these properties were compared both to a control (100% wood parlicles) and to PB made from the same content of unextracted bark. The results showed that, while the mechanical properties of the PB made from extracted black spruce and trembling aspen hark decreased with increasing bark content, LE increased. PB made of fine particles often showed higher IB and lower TS values. Hot water extraction of the bark had a detrimental effect oil all the physical and mechanical properties of the PBs produced except for the Janka hardness, where no significant decrease was found. The MOE and MOR of the PBs made from 50 percent black spruce and trembling aspen bark met the requirements of the ANSI standard for commercial (M-1) and underlayment (PBU) grades. In contrast, the dimensional properties (TS and LE) of all the boards did not fulfill the minimum requirements of the ANISI standard.