Enhancing fast-growing wood properties via rosin-modified cellulose: superior hydrophobicity and dimensional stability.

Fast-growing wood is rich in hydroxyl groups, which are sensitive to water and readily absorb moisture in humid environments, leading to a reduction in the mechanical properties of the wood and limiting its applications. Herein, a silicone modified rosin-based hydrophobic agent (SRA) was synthesized from a biomass resource, tetrahydro rosin acids (TRA), and (3-glycidyloxypropyl)triethoxysilane (KH-561) through a ring-opening reaction. The triethoxy groups in the SRA structure facilitate the formation of covalent bonds with the hydroxyl groups of cellulose in the wood, effectively anchoring the active components within the wood matrix and filling its porous structure. The addition of SRA not only reduced the water absorption rate of the wood from 112 % to 34 % after a 12-day immersion in water, and increased the water contact angle of the wood from 100° to 127°, but also greatly improved the dimensional stability of the wood with a 52 % antiswelling efficiency. Furthermore, the solid crosslinked network structure enhances the mechanical properties of the wood, increasing its axial tensile strength from 43 MPa to ∼65 MPa. This study is significant for utilizing biomass resources to improve the performance of fast-growing wood and expand its application fields.