Polyol/Alkali System Drives In Situ Cell Wall Reconstruction for Bamboo Self-Bonding

Abstract Traditional bamboo bonding processes face challenges such as formaldehyde emissions, procedural complexity, and high costs. This study proposed a strategy for in situ reconstruction of bamboo cell walls using a polyol/alkali system to achieve bamboo bonding. First, an aqueous NaOH coating selectively dissolved partial hemicellulose from bamboo, increasing cell wall porosity and releasing abundant hydroxyl groups. The subsequent application of polyol reagents (glycerol and PEG400) to bamboo surfaces initiated the melting and reconstruction of the cell wall through hot-pressing. In situ real-time observations demonstrated that self-bonding interfaces are formed through both cell wall contact fusion and molten material filling. The resulting bonding interface relies on physical interlocking induced by cell wall reconstruction, C–C covalent bonds formed by aromatic units in bamboo lignin, and hydrogen bonding generated by hydroxyl groups. Under this bamboo self-bonding strategy, the dry and wet bonding strengths reach 7.12 and 6.45 MPa, respectively. The modulus of rupture and modulus of elasticity of the laminated bamboo lumber are 125.69 MPa and 18.55 GPa, respectively. The polyol/alkali bamboo self-bonding system features low-cost reagents, operational simplicity, formaldehyde-free, and excellent mechanical performance, which offers a sustainable alternative for the fabrication of furniture and building materials.