A new strategy for the hydrophobization of bamboo via laccase catalyzed dodecyl gallate coupling with hydrothermal pretreatment

Hydrophobic modifications of bamboo could negate its hygroscopicity to improve the durability of bamboo products. Dodecyl gallate (DG), a plant-based hydrophobic reagent, can be used to increase the hydrophobicity of bamboo, but the lack of bonding attachments restricts its efficiency. Herein, for the first time, an integrated strategy of bamboo hydrophobic modification was established using hydrothermal pretreatment coupled with laccase-catalyzed DG modification. The results showed the hydrophobicity was increased from 36.0° to 117.9° and the stable hydrophobic time of bamboo increased up to 6 times after modification. A significant antibacterial property and improvement of mold resistance were observed from modified bamboo, which were caused by DG bonding with bamboo. The results of hydrothermal pretreatment shown that lignin migrated to bamboo surface and accompanied with a concentration increase from 54.3% to 72.8%, which was beneficial to fixing DG for conferring its multiple performances. The reaction between bamboo lignin and DG confirmed that lignin as the targeted biopolymers within bamboo constituents, and ether bonds were identified as the primary connections between DG and bamboo lignin via multiple characterization methods. This study demonstrated a reliable hydrophobic modification avenue to improve antimicrobial properties and shed new light on bamboo pretreatment and laccase-catalyzed modification.