A SaBOX/Co catalyst designed for facile access to the challenging copolymers of vinyl ester and methacrylate

Copolymerization of more activated methacrylates and less activated vinyl esters is challenging because of their large difference in reactivity ratio. This severely limits the development of high-performance materials. Herein, we design a side-armed bisoxazoline (SaBOX)/CoBr₂ catalyst with sheltered coordination environment to achieve strong binding ability to propagating radicals in photoinduced cobalt-mediated radical polymerization (CMRP) of vinyl ester and methacrylate. This enables the efficient synthesis and structure regulation of methacrylate-vinyl ester copolymers. The catalytic system efficiently and directly produces di- and tri-block copolymers via in-situ chain extension. Moreover, homogeneous random copolymers of vinyl ester and methacrylate are also facilely synthesized. The mechanistic studies are consistent with the polymerization results, which validate the CMRP mechanism and our catalyst design concept.