Utilization of commercially available resource for particleboard and MDF. Part III. Evaluation of mountain pine beetle-killed lodgepole pine as raw material for particleboard manufacturing
To evaluate the effects of mountain pine beetle-killed (MPB) lodgepole pine on particleboard performance, a series of homogeneous particleboards were manufactured from green and MPB pine particles at five mixing ratios (100:0, 75:25, 50:50, 25:75, 0:100). Particles were characterized for wood chemical properties (pH value and acid buffer capacity) and particle size distribution. Particleboards were evaluated by testing physical and mechanical properties such as internal bond (IB) strength, modulus of rupture (MOR), modulus of elasticity (MOE), thickness swelling (TS) and water absorption (WA), and linear expansion (LE).
Green pine and MPB pine showed similar chemical properties (in terms of pH value and acid buffer capacity) and particle size distribution. Based on these wood chemical and physical characteristics, it was expected that the use of MPB pine as substitution of green pine would not likely cause a bonding problem in particleboard manufacturing. Evaluation of board physical and mechanical properties indicates that MPB pine particles could substitute green pine particles up to 100% without a negative impact on board properties such as IB, MOR/MOE, and TS/WA. In fact, these board properties were improved with the addition of MPB pine, especially at 25% and 50% MPB pine particle substitution levels. A negative impact was observed only for LE. An increase in MPB pine in the substitution of fresh pine from 0% to 50% reduced the LE value; however, a further increase, up to 100%, increased the LE value. From this study, it can be concluded that MPB pine can be safely used to substitute fresh pine, at substitution levels from 50% to 75%, in manufacturing particleboard. Particleboard made from MPB lodgepole pine appeared darker in colour as compared with boards made from green lodgepole pine because of the presence of blue stain in the MPB wood.