Oriented strand board with improved dimensional stability by extraction of hemicelluloses

Oriented strand board (OSB) panels are commonly used for wooden building structures such as Walls, floors, ceilings, and furniture. These wood composites are manufactured with small wooden strands held together in specific orientations by adhesives. Other additives such as wax might be added to reduce water absorption. One of the limitations of the panels produced today is their poor performance under high humidity conditions. The goal of the present work was 1) to extract hemicelluloses from pine wood strands before the fabrication of OSB panels and 2) to test the impact of the pretreatment on the dimensional stability of these panels. For that purpose, pressure-assisted hydrothermal processes at three different temperatures (120, 140, and 160oC) were performed for 45 min of extraction time in each case. Hemicelluloses in treated wood strands were quantified using high-performance liquid chromatography. Water absorption, thickness swell, MOE, MOR, and internal bond strength were measured to assess the influence of the pretreatment on OBS properties. According to the results, a hydrothermal pretreatment is beneficial for the performance of OSB panels at high humidity levels. The pretreatment of pine strands at 160oC allowed for the maximum removal of hemicelluloses, without a significant degradation of cellulose or lignin, and the OSB panels pretreated with these pinewood strands displayed the best performance in dimensional stability under wet conditions.