Synergistic effects of thermal compression temperature and density on the self-bonding mechanism and properties of binderless bamboo scrimber

Bamboo self-bonding represents an eco-friendly adhesive-free approach for fabricating high-performance composites. High-performance multipurpose bamboo scrimber fabricated via thermal pressing conforms to the chemical characteristics and high-density structure associated with self-bonding; however, the contribution of bamboo autohesion to its properties remains insufficiently investigated. Systematic investigations were conducted to elucidate the effects of thermal compression parameters (temperature and density) on bonding strength, flexural performance, and moisture resistance of BBS by multi-scale characterization such as SEM, XPS, FTIR NMR, XRD, etc. The results indicate that elevated thermal compression temperatures were found to accelerate hemicellulose pyrolysis, leading to increased furfural generation and enhanced lignin cross-linking, which collectively facilitated the self-bonding of BBS. The high degree of densification by thermal compression reduced the number and size of inter- and intra-cellular pores in BBS, thus enhancing the mechanical interlocking between cells to improve the self-bonding strength, specifically the plastic deformation of parenchyma cells. The BBS fabricated under a temperature of 160 ℃ and a density of 1.2 g/cm 3 exhibited optimal bending properties (MOR: 145.1 MPa; MOE: 18.5 GPa), whereas that prepared at 170 ℃ and a density of 1.2 g/cm 3 showed optimal internal bonding strength (1.67 MPa) and moisture resistance. By effectively utilizing bamboo’s chemical properties and self-bonding capabilities under thermal compression, while addressing its shape, size, and performance limitations to prepare high-yield BBS, the utility scope of bamboo can be expanded. This can effectively conserve conserves fossil resources, enhance bamboo valorization, and support sustainable forestry cycles. • Development of a fully binderless bamboo scrimber via thermal compression. • Self-bonding mechanism involves chemical cross-linking and physical interlocking. • Optimal BBS achieved at 170 °C & 1.2 g/cm 3 , maxing bonding & moisture resistance. • 160 °C favored strength, 170 °C optimized bonding, revealing a performance trade-off. • Offers a green path to valorize bamboo, curtailing reliance on fossil resources.