Polyurethanes have been widely used in coatings, adhesives and inks due to the diversity of properties that can be engineered into their design. Although polyurethanes are used in numerous applications, there is an unmet need for polyurethane adhesives for underwater adhesion. Here, we demonstrate the design of polyurethanes synthesized from photoresponsive p-alkoxyphenacyl diol, as a chain extender, along with polypropylene glycol (PPG) 2000 to create an initiator-free crosslinkable polyurethane. Traditionally, the alkoxyphenacyl (AP) group has been used as a protecting group due to its ability to undergo chain scission under UV light. In this work, we demonstrate that AP containing polyurethanes function as adhesives as a result of an unexpected crosslinking reaction. With increasing time of irradiation, we observed a shift to adhesive failure, wherein less adhesive remains on the bonded substrate. This observation indicates increase in cohesive strength (due to crosslinking) within the polymer. Rheology measurements support this hypothesis. Due to the polyurethane hydrophobicity, the adhesive can repel water when tested in wet conditions, and effectively bind to the substrate.   <br/> <br/>

Photoinduced polymer crosslinking of alkoxyphenacyl based polyurethanes and their application in underwater adhesion

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.