Strengthening of densified wood and wood honeycomb based on cell wall microstructure regulation.

Engineering materials selection requires a balance between mechanical strength, environmental impact, and cost-effectiveness. Wood presents distinct advantages, including economy, renewability, and low density. However, the low absolute strength and inherent susceptibility of wood to moisture significantly limit its applications in various engineering fields. Here, the reinforcing effect of cellulose fibers and the advantages of the natural porous structure of wood are significantly enhanced by the combination of densification and alkali treatment. With increased alkali treatment time to remove lignin, the tensile strength of densified pine increased to a maximum of 131 MPa (5 times that of natural pine) and then decreased. The specific energy absorption of the densified wood honeycomb structures is twice that of an engineered aluminum honeycomb, and the wood can be successfully molded into structural components through the regulation of cell wall microstructure for tailored mechanical properties.