Bioinspired tannic acid-based adhesive with hyperbranched polymer and nano-Mg(OH)2 hybrids for high-performance, flame-retardant, and sustainable

초록

The development of innovative biomass-based, flame-retardant plywood is set to overcome the dual technical barriers of formaldehyde emissions from conventional resin systems and the inherent flammability of wood. Creating sustainable adhesives to replace hazardous formaldehyde-based resins represents an urgent need in material science, tackling current limitations in eco-friendly alternatives that balance high performance with multifunctionality. Stepping into the structural shoes of marine arthropod cuticles as an inspiration, this study employed the Schiff base/Michael addition reaction to covalently cross-link oxidized tannins with aminofunctionalized hyperbranched polymers and Mg(OH)2-NH2 nanohybrids to design a bio-based adhesive system. Comprehensive characterization through mechanical testing (dry/wet adhesion strength), flame retardancy evaluation (Limiting Oxygen Index (LOI) and Cone Calorimeter-Based Thermal Analysis), and thermal analysis demonstrated that the hierarchical particle-chain structure demonstrates a commendable dry strength of 1.52 MPa, while exhibiting 88 % retention in 63 degrees C water and 70 % in boiling water, along with excellent flame resistance and robust thermal stability. The phenolic-amine synergistic system improved interfacial adhesion, crosslinking density, and flame retardancy through covalent bonding, gas-phase radical quenching, and char-layer barrier mechanisms. This biomimetic design establishes a circular economy paradigm for converting natural polyphenols into multifunctional adhesives, providing theoretical insights into dynamic covalent networks and scalable solutions for eco-friendly wood composites.

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