In situ retention of lignin-rich bamboo green effectively improves the surface properties of flattened bamboo.

Bamboo has tremendous carbon sequestration potential, and bamboo green is underutilized. This work devised a green-keeping technique in bamboo flattening that preserved natural bamboo green in-situ. The impacts of flattening and green-keeping on bamboo morphology, chemical composition, physical qualities, and composite applications were examined. Bamboo cells were wrinkled after flattening, while bamboo green exhibited a more homogenous surface. Bamboo cellulose crystallinity increased after flattening, hemicellulose deteriorated little, and relative lignin content increased. The hydrophobicity and mildew resistance of the surface of G-FB (green-kept flattened bamboo board) were improved. Compared to untreated bamboo, FB and G-FB had 61.1 % and 49.5 % higher tensile strength and 8.0 % and 33.2 % higher MOR. G-FB-made flooring exhibited a MOR of 134.7 MPa and upgraded surface properties. Bamboo green preservation boosted utilization of materials and improved flattened bamboo's exterior surface without affecting lamination bonding. Simple bamboo green preservation multifunctionalizes flattened bamboo composites.