Preparation of tannic acid-based recyclable adhesive with high adhesion property, low curing temperature, and environmental tolerance

Tannin-based adhesives have demonstrated promise in decreasing dependence on petrochemical resources linked to formaldehyde-based resins. However, current tannin-based adhesives face challenges due to the incorporation of expensive or toxic reagents such as isocyanate, epoxy, and formaldehyde, as well as the inability to be recycled. This study presents a simple and eco-friendly approach for producing a tannic acid-based recyclable adhesive (TA-BVB) by employing tannic acid and 1,4-butanediol divinyl ether through acetal reactions. The resulting adhesive can be cured at a low temperature of 70℃ and demonstrated high bonding strength on wood and aluminum sheets, measuring 4.45 MPa and 5.44 MPa, respectively. Notably, the adhesive maintained its adhesion strength even under harsh conditions, including high temperatures (100℃), liquid nitrogen (-196℃), and exposure to various solvents. Moreover, the adhesive showcased excellent reusability, retaining over 100 % and 86 % of bonding strength after the first and second rounds of hot pressing, respectively. This adhesive can be repaired using infrared laser irradiation and displayed remarkable mold resistance. This research underscores the potential of tannic acid in developing environmentally friendly, high-performance, recyclable adhesives with versatile applications.