Abstract
Natural bamboo is rapidly replacing wood, but it is highly hygroscopic and has poor dimensional stability. Herein, Moso bamboo was subjected to hygrothermal treatment at different temperatures. The hydrophobicity and dimensional stability of bamboo increased, as indicated by the 16.5% decrease in volumetric swelling and three-fold increase in the contact angle at 220 °C. The fibers and parenchyma cells delaminated, and pores appeared after treatment at 200 °C. These changes were attributed to the significant degradation of hemicelluloses. The acetyl groups of hemicelluloses decomposed into acetic acid. The apparent crystallinity of cellulose increased mainly due to the reduced hemicellulose content. Furthermore, a breakage of xylan and β-O-4 bonds was observed, and S units were condensed after treatment at 220 °C. In addition, the syringyl/guaiacyl ratio showed more than a five-fold increase, while associated ferulic acid decreased after hygrothermal treatment, indicating that the dense structure of the cell walls was broken. These data were used to propose a mechanism for changes in the bamboo cell walls during hygrothermal treatment. This simple and environmentally-friendly approach holds great potential for use in high-humidity environments.
Funding source: National Natural Science Foundation of China 10.13039/501100001809
Award Identifier / Grant number: 31500472
Award Identifier / Grant number: 31770599
Award Identifier / Grant number: 31670565
Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: The authors would like to acknowledge financial support from the National Natural Science Foundation of China (31500472, 31770599, and 31670565).
Conflict of interest statement: The authors declare no conflicts of interest.
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