Thermally Compressed Poplar Wood (TCW): Physical and Mechanical Properties

Various thermal modification techniques are used to improve some properties of wood materials. Thermally compressed wood (TCW) is obtained by using a hot-press. This study investigates the effect of thermal compression on the density, vertical density profile (VDP), moisture content (MC), thickness swelling (TS), Janka hardness, and drying characteristics of the poplar wood boards. The experimental boards were cut from poplar wood (Populus spp). The boards with dimensions of 100 mm by 500 mm by 25 mm were thermally compressed at press temperature of either 150 °C or 170 °C, press pressure of either 1 or 2 MPa for 45 minutes in a hot-press. A total of 10 experimental boards were prepared - two boards for each group plus two for control. The results obtained in this study indicated that the density and Janka hardness values increased with the increase of the press pressure. The thermal compression process decreased the thickness of the boards. The thickness reduction increased with the increase of the press pressure. An improvement was not seen in the TS values of the samples when compared to those of the untreated samples. This study revealed that the thermal compression technique should be used to improve some properties of poplar wood. In this way better use could be made of low-cost poplar wood.