Effect of hot water extracted hardwood and softwood chips on particleboard properties

The affinity of particleboard (PB) to water is one of the main limitations for using PB in moisture-rich environments. PB dimensional stability and durability can be improved by reducing the available hydroxyl groups in wood through hemicellulose removal, for example, by hot water extraction (HWE), which increases wood resistance to moisture uptake. The resulting liquid fraction from HWE is rich in hemicelluloses and can be used for chemicals and fuels, and the solid fraction is less hydrophilic. The objective of this study was to investigate the effects of HWE of softwood chips (conducted at 160°C and 90 min) and hardwood chips (160°C and 120 min) on the properties of PB panels. HWE increased compressibility and reduced springback by 34% and 44% for pine and maple chips, respectively, which positively impacted the PB properties. Water absorption of pine PB panels was lowered by 35% and that of maple PB panels by 30%, while reduction of thickness swelling was lowered by 39% for pine PB and 56% for maple PB after 24 h of immersion in water. The mechanical properties were not significantly affected.