Sustainable bamboo modification via chitosan/tannic acid/silver bio-based composite system: A facile spray-deposition strategy for enhanced mildew resistance, dimensional stability, and mechanical performance.

Bamboo's intrinsic susceptibility to mold, stemming from its hydrophilic nature and abundant nutrient content, poses significant challenges for industrial applications. Traditional impregnation modification strategies suffer the disadvantage of long processing time, low modifier utilization efficiency, and limitations in scalability for industrial production. To address these issues, this work proposed a novel, facile, and sustainable modification strategy. A sequential treatment process was developed, beginning with alkaline delignification to eliminate nutrients from bamboo, followed by in situ deposition of chitosan/tannic acid/silver composites (CS/TA/Ag) through precision spraying. This approach constructed a three-dimensional cross-linked network within the bamboo matrix, fundamentally altering its surface characteristics. The modified bamboo exhibited excellent mold resistance against Penicillium citrinum and Trichoderma viride, with inhibition rates of 93.75 % and 100 %, respectively. Benefiting from the bio-based inorganic complexes, the treated bamboo maintained a good modulus of rupture (187.23 MPa) and enhanced dimensional stability. Overall, this work has shed new light on the development of sustainable and high-performance biomass materials, offering promising potential for scaling up production in the bamboo industry.