Facile, Modular Transformations of RAFT Block Copolymers via Sequential Isocyanate and Thiol-ene Reactions
Polymers and High Performance Materials
We describe a robust strategy utilizing reversible addition-fragmentation chain transfer (RAFT) polymerization and sequential transformations involving carbamate formation and thiol-ene click addition to synthesize well-defined functional block copolymers. The hydroxy-functional block copolymer scaffold, poly[(N,N-dimethylacrylamide)-b-(N-(2-hydroxyethyl)acrylamide)] (PDMA(n)-b-PHEA(m)) was first prepared via RAFT, requiring no protecting group chemistry. The hydroxyl groups of the HEA block were then reacted with 2-(acryloyloxy)ethylisocyanate (AOI) or allylisocyanate (AI) resulting in acrylate- and allyl-functionalized copolymer precursors, respectively. The efficiencies of both Michael and free radical-mediated thiol-ene addition reactions were investigated using model thiol compounds having alkyl, aryl, hydroxyl, carboxylic acid, amine and amino acid functionalities. The steps of RAFT polymerization, isocyanate-hydroxyl coupling and thiol-ene addition can be accomplished under mild conditions, thus offering a facile, modular route to the synthesis of functional copolymers from a single polymeric precursor.
Flores, J. D.,
Treat, N. J.,
York, A. W.,
McCormick, C. L.
(2011). Facile, Modular Transformations of RAFT Block Copolymers via Sequential Isocyanate and Thiol-ene Reactions. Polymer Chemistry, 2(9), 1976-1985.
Available at: http://aquila.usm.edu/fac_pubs/388