Versatile Pathway to Functional Telechelics via RAFT Polymerization and Click Chemistry

Abstract

Two novel azidofunctionalized chain transfer agents (CTAs) were prepared and subsequently employed to mediate the reversible addition−fragmentation chain transfer (RAFT) polymerizations of styrene (Sty) and N,N-dimethylacrylamide (DMA) under a variety of conditions. Trithiocarbonate 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl-propionic acid 3-azido-propyl ester and dithioester 4-cyano-4-methyl-4-thiobenzoylsulfanyl-butyric acid 3-azido-propyl ester successfully mediated the polymerizations of Sty and DMA. Both RAFT polymerizations exhibited pseudo-first-order kinetics and a linear Mn dependence with conversion. The resulting homopolymers (Mn = 4 − 22 × 103 g/mol and Mw/Mn ≤ 1.33) were demonstrated to have retained ω end group functionality, as evidenced by the successful formation of block copolymers. The α-azido terminal polymers and the azidofunctionalized CTAs were coupled with high efficiency by click chemistry to various alkynes (propargyl acrylate, propargyl methacrylate, and propargyl alcohol) in the presence of a Cu(I) catalyst, demonstrating the ability to prepare a range of functional telechelics and CTAs.