Effect of thermal modification by hot pressing on performance properties of paulownia wood boards

The goal of this study was to investigate the effects of thermal modification by hot-pressing on the performance properties of paulownia wood boards. The boards were thermally modified by hot-pressing method under different pressure and temperature levels. As two boards for each modification group plus two for unmodified, totally 10 experimental wood boards were prepared in this study. Main density, vertical density profile (VDP), thickness swell (TS), water absorption (WA), moisture content (MC), and hardness tests were carried out to evaluate the performance properties of the thermally modified or unmodified wood boards. The results obtained in this study indicated that surface density of the boards increased with increasing press pressure. The thermal modification negatively affected the TS and WA values of the boards. Hardness values of the wood boards were significantly improved by the thermal modification. The results of this research revealed that the thermally compressing method could be used to improve end-use properties of low-density wood materials made from fast-growing tree species such as paulownia, poplar, eucalyptus etc. Thus low-value wood materials could be converted to value-added products. In addition, sustainable management of natural resources could be achieved by using the thermal modification method.

► The last decades developments in the arena of wood modification have accelerated considerably. ► The thermal modification process has a significant factor influencing of the physical and mechanical properties of the wood-based materials. ► The improved characteristics of the thermally modified wood-based materials offer many potential and attractive new opportunities to wood products industry.