Rapid Underwater Adhesive Utilizing Crosslinker and Amine Catalyst-Filled Microcapsules

Rapidly curing underwater adhesives were tested on untreated substrates and demonstrated high ultimate shear strength. An isocyanate resin was combined with microcapsules containing both a polyol crosslinker and a tertiary amine catalyst. The polyurea microcapsules were synthesized on a large scale via an inverse Pickering emulsion utilizing inexpensive reagents. The microcapsules were stable to ambient conditions and gentle mixing but released their contents when appropriate shearing forces were applied. The final polyurethane adhesive achieved high bonding strength (2.88 ± 0.8 MPa) over a short time period (1 min).