Self-healing high-performance vitrimer adhesives derived from peach gum polysaccharide via vinylogous urethane...

Developing high-performance, closed-loop recyclable, and bio-based adhesives remains a significant challenge due to the inherent trade-off between crosslinking density and reprocessability. Herein, we report a bio-based vitrimer adhesive derived from peach gum polysaccharide (PGP) via vinylogous urethane (VU) chemistry. PGP was first modified with tert-butyl acetoacetate, followed by crosslinking with a fatty acid-derived diamine to form dynamic VU networks (PUV-x). The resulting PUV-1.0 network exhibits excellent mechanical properties (tensile strength up to 28.5 MPa, Young's modulus of 427.0 MPa, and elongation at break of 67.0%) and high thermal stability (T_s = 174.5 °C). Benefiting from the associative exchange of VU bonds, the material demonstrates rapid stress relaxation (activation energy of 30.4 KJ·mol^-1), efficient self-healing (16 min at 100 °C) of surface scratches, and weldability. Moreover, the PUV-1.0 adhesive exhibits strong adhesion to various substrates (wood, steel, and glass), achieving an adhesion strength of up to 18.9 MPa on wood. It also maintains stable bonding performance under extreme temperatures (-22 to 100 °C) and in harsh environments (water, acid, alkali, sweater, and ethanol). The network can be chemically degraded and closed-loop recycled via transamination reactions, and the adhesive can be removed on demand from different substrates. This work provides a high-performance, and recyclable vitrimer adhesive platform, highlighting the potential of PGP in advanced bio-based materials.