High-Pressure Preparation of High-Strength Wood Materials

Mineral resources on Earth are finite, but wood is renewable. Therefore, replacing limited industrial materials with modified wood remains a long-term pursuit. This study processed samples of three wood types, including balsa (Ochroma lagopus), basswood (Tilia tuan), and African blackwood (Dalbergia melanoxylon), with a large volume cubic press to compress these samples at room temperature under high pressure. The effects of high-pressure treatment on the air dry density, compressive strength, and elastic modulus of the three wood species were analyzed, and changes in their internal microstructures were observed using CT and scanning electron microscope. The results showed that the physical and mechanical properties of all three wood species improved. After high-pressure processing at 5.50 GPa, the density of balsa, basswood, and African blackwood increased by 239%, 112%, and 11%, respectively. Additionally, the surface hardness increased by 79%, 46%, and 15%, respectively, and the compressive strength increased by 33%, 9%, and 28%, respectively. Notably, the specific strength of compressed African blackwood (101.55 kJ/kg) approaches that of aluminum alloys (109.23 kJ/kg). The results demonstrate that African blackwood is lighter than ceramic materials. Furthermore, this wood offers superior electrical insulation and thermal insulation compared to aluminum alloy. Crucially, African blackwood possesses high specific strength, and this property gives it significant potential to replace aluminum alloy in numerous special environments. Such application supports sustainable development for future industries. In conclusion, this research opens new possibilities for high-value wood applications.