Degradable Adhesives as Sustainable Alternatives to Acrylics via Ring-Opening Radical Polymerization of Vinylcyclopropanes.

Acrylic pressure-sensitive adhesives (PSAs) are loosely crosslinked polymer networks widely used across various industries. However, the network structure and inert nature of the acrylic polymer backbone present sustainability challenges. To address these issues, efforts are being made to incorporate degradable units into the polymer backbone. Yet, two key obstacles remain: i) the polymer does not degrade into sufficiently small fragments, and ii) the adhesive and viscoelastic properties are often inferior to those of conventional acrylic polymers. In this study, we developed a PSA utilizing vinylcyclopropane (VCP)-based monomers and a VCP-based crosslinker, achieving molecular-level degradation while maintaining adhesive performance and viscoelastic properties comparable to traditional acrylic PSAs. Under optimized polymerization conditions, the polymer incorporates ozone-labile double bonds into its backbone, enabling controlled molecular degradation without compromising its properties. By synthesizing and strategically combining various VCP-based monomers, we developed PSAs with tailored adhesion and viscoelastic behavior on par with conventional acrylic PSAs. These advancements indicate that the degradable polymers and PSAs developed in this study are poised for practical application in the near future.