Bio-Inspired Gelatin-Based Adhesive Modified with Waterborne Polyurethane on Click Chemistry

As a non-toxic, highly reactive biomass material, gelatin is wildly used as the component of biomass-based adhesive. However, like most aqueous adhesives, gelatin-based adhesives suffer from long solidifying time or high solidifying temperature due to the low volatility of water, which highly limits the application potential of gelatin based adhesives. Inspired by the fast adhesion of marine organisms through the formation of chemical crosslinks, herein, a kind of low temperature curable eco-friendly gelatin-based adhesive with good adhesive properties and fast curing at low temperature is developed by introducing clicking chemical Diels-Alder (DA) reaction between blocked waterborne polyurethane (MWPU) and gelatin. The furfuryl glycidyl ether (FGE) and 4-Maleimidophenol (4-HPM) for the DA reaction are grafted on gelatin, and the end-capping of MWPU, respectively. With the addition of MWPU and FGE, the cross-linking degree of gelatin increased, and the adhesion properties of the adhesive were improved. The shear strength and T-peel strength of the modified adhesive reached 0.95 MPa and 1.42 N/mm, respectively, after the curing time of 8 min at 40 degrees C, which can meet the application requirements as adhesive for bio-medical use.