Physico-mechanical properties of thermally treated poplar OSB

Oriented strand board (OSB) are widely marketed for several applications, from building to packaging. The manufacturing of poplar OSB has recently started in Northern Italy, representing a relevant innovation in the sector, given that this product is usually made of coniferous wood. Thermal treatment is nowadays widely used for increasing the dimensional stability and the durability of wood. The drawback is, however, that the mechanical performance of the treated wood product is reduced. The objective of this research was to analyze the effect of thermo-vacuum treatment on the characteristics of poplar OSB. To this purpose, boards 15 mm thick and with a density of 590 kg/m3 were drawn from the standard production of the manufacturer and thermally treated under vacuum conditions at 190 °C for 2 h. Their mass loss, bending strength, modulus of elasticity, internal bond and swelling were determined. In addition, color change and wettability were studied before and after a weathering test. The thermal treatment significantly changed the properties of poplar OSB. The mass, the bending strength, the modulus of elasticity and the internal bond decreased with different intensities. The swelling after immersion in water decreased. The color switched toward a darker tone and the wettability decreased. After an accelerated weathering test (AWT), the color lightened, and the wettability increased. Overall, this study broadened the knowledge about the thermal treatment of this wood-based panel, which could enable new applications with particular attention to non-structural uses in humid conditions.