Wood, a renewable and versatile biopolymer, has been a fundamental material to construct traditional and advanced composites for building construction, furniture, transparent composites, and various other applications. Despite its many advantages, including its aesthetic appeal, workability, and relatively low cost, wood possesses inherent limitations such as susceptibility to biological, flame and mechanical damages, which can significantly shorten its lifespan, especially in harsh environments. Thus, enhancing the properties of wood to improve its durability, strength, and resistance to environmental factors has been a critical area of research. Recent studies demonstrate that delignification, chemical impregnation, and densification significantly improve the performance of wood composites by enhancing micro/nanofibril bonding within the cell wall, thereby increasing its strength and durability. Lignin, a complex polymer, acts as a binder for cellulose microfibrils in the cell wall, giving wood its rigidity and structural integrity. By removing lignin, individual cellulose fibrils become more accessible and can bond to each other more easily with densification. Stronger microfibril bonding within the cell wall directly contributes to improved mechanical properties such as flexural strength, stiffness, and toughness. This work demonstrates a process of developing high-performance wood material through combined microwave energy-deep eutectic solvent (MWE-DES) pretreatment, resin/silica impregnation, and high-temperature densification to improve its mechanical, structural, dimensional stability and biological properties for advanced structural uses. The MWE-DES treated basswood was shown to have a highly porous network structure with partial removal of lignin and hemicellulose. The bending strength of modified wood with PF resin and sodium silicate, respectively increased by 72% and 61.6%, compared to the raw wood properties. The high mechanical strength of wood is due to the combined effect of enhanced cell-wall fibril bonding at micro/nanoscale, strengthening with cured resin, and/or Si O Si bonding between wood fibril and silica. Additionally, thermal stability, dimensional stability, and termite resistance of the treated wood composites were also improved. The lignin, hemicellulose, and used DES solvent were shown to be recoverable with an environmentally friendly treatment process.

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