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

Abstract

As a non-toxic, highly reactive biomass material, gelatin is wildly used as the component of biomass-based adhe-sive. 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-Maleimidophe-nol (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°C, which can meet the application requirements as adhesive for bio-medical use.