Cellulose‐Tannin‐Glycerol (CTG): A Biomass‐Based, Recyclable, and High‐Performance Adhesive via Water‐Regulated Cohesion

ABSTRACT Nowadays, with increasing environmental awareness, researchers have increasingly focused on developing recyclable or degradable adhesives with superior bonding strength and moisture resistance derived from biomass materials. Although the formation of interfacial covalent‐crosslinking is a challenge, regulating non‐covalent interactions is a rational path. Here, the cellulose‐tannin‐glycerol (CTG) adhesive was prepared by adjusting the ratio of free water to bound water within the adhesive using glycerol triglycidyl ether, thereby regulating its cohesion. The optimal ratio of free water to bound water within the adhesive facilitated adequate wetting of substrates to restrain stress relaxation and crack growth. The maximum bonding strength of the steel substrate exceeded 40 MPa. Furthermore, CTG adhesive was all biomass‐based adhesive with facile preparation methods, demonstrating robust bonding strength, solvent resistance, and aging resistance, and could be fully recycled by pH adjustment and biodegraded efficiently. This work provides a breakthrough solution to the environmental pollution and performance bottlenecks of traditional petroleum‐based adhesives.