In this paper, Berkovich depth-sensing indentation has been used to study the effects of the temperature-dependent quasi-static mechanical properties and creep deformation of heat-treated wood at temperatures from 20 °C to 180 °C. The characteristics of the load–depth curve, creep strain rate, creep compliance, and creep stress exponent of heat-treated wood are evaluated. The results showed that high temperature heat treatment improved the hardness of wood cell walls and reduced the creep rate of wood cell walls. This is mainly due to the improvement of the crystallinity of the cellulose, and the recondensation and crosslinking reaction of the lignocellulose structure. The Burgers model is well fitted to study the creep behavior of heat-treated wood cell walls under different temperatures.

The deposition of TiO₂/ZnO on heat-treated wood was prepared by a hydrothermal reaction and sol-gel method. Highly hydrophobic wood was successfully prepared with low surface free energy. The surface-modified wood samples were characterized by 3D-laser shape measurement microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and Fourier transform infrared spectroscopy for the microstructure and chemical composition investigation. The deposited TiO₂ or ZnO markedly made the wood surface brighter, which was demonstrated by visual observation and spectrophotometer. The TiO₂/ZnO particles were successfully loaded onto the surface of the wood, proven by SEM-EDS and FTIR analyses. The contact angle of TiO₂ and ZnO-modified wood reached 123.9° and 134.1° respectively, which is obviously higher than that of the control at 88.9°. The hydrophobic properties of the TiO₂/ZnO modified wood samples were directly related to the shapes of clusters and spheres of particles, which increased the roughness of the wood surface. This study shows the hydrophobic properties of the TiO₂/ZnO-modified wood and provides the color and roughness changes for the painting process of heat-treated wood.

Heat-treated wood is widely used for outdoor furniture manufacturing. However, it is susceptible to against physical degradation such as cracking and discoloration. This study involved heat-treated wood at three different temperatures of 180 °C, 200 °C and 220 °C was acetylated using vacuum-pressure impregnation methods to enhance photostability, dimensional and thermal stability. The laboratory chromaticity data indicated a substantial enhancement of the photostability of the acetylated heat-treated wood. The color difference was reduced from 11.89 to 10.08 for the 180 °C treatment, then from 10.24 to 9.02 for the 200 °C treatment, and from 8.31 to 8.11 for the 220 °C treatment compared to unmodified wood at the same temperature. The microstructure analysis and chemical composition study suggested that the hydroxyl groups were greatly reduced, rendering the microstructure and chemical composition of wood relatively stable. In addition, the results of water contact angle, water absorption, swelling and shrinking data show that acetylated wood exhibits lower hydrophilicity and greater dimensional stability. Thermo-gravimetric analysis reveals that acetylated wood maintained better thermal stability, as evidenced by the greater maximum temperature for thermal degradation. The weathering resistance of heat-treated wood was significantly improved by acetylation treatment.