A Facile Route to Functional Hyperbranched Polymers by Combining Reversible Addition-Fragmentation Chain Transfer Polymerization, Thiol-Yne Chemistry, and Postpolymerization Modification Strategies.

Abstract

This contribution reports on the preparation of functional hyperbranched polystyrene-based materials via a combination of reversible addition-fragmentation chain transfer (RAFT) polymerization, thiol-yne chemistry, and postpolymerization modification reactions. The thiol-yne approach allows the rapid preparation of hyperbranched polymers under mild reaction conditions from polymeric chains bearing a thiol group at one chain end and an alkyne moiety at the other. Postpolymerization modifications of the focal thiol and peripheral alkyne functionalities present within the hyperbranched structures were conducted using two highly efficient strategies, i.e., phosphine-catalyzed thiol-ene reaction and copper-catalyzed azide-alkyne cycloaddition (CuAAC), respectively. In addition to introducing functionalities by postpolymerization modification onto the periphery of the hyperbranched polymers, the interior of the globular structure could also be functionalized by taking advantage of the isocyanate chemical handle of a poly(styrene-co-3-isopropenyl-α,α-dimethylbenzyl isocyanate) (P(S-co-TMI)) copolymer. The combination of these strategies provides an elegant tool for the elaboration of a wide variety of multifunctional hyperbranched structures.