Combination of Ring-Opening Polymerization and “Click Chemistry”: Toward Functionalization and Grafting of Poly(ε-caprolactone)

Abstract

A straightforward strategy is proposed for the derivatization of poly(e-caprolactone) (PCL). First, statistical copolymerization of α-chloro-e-caprolactone (αCleCL) with e-caprolactone (eCL) was initiated by 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP). In a second step, pendent chlorides were converted into azides by reaction with sodium azide. Finally, duly substituted terminal alkynes were reacted with pendent azides by copper-catalyzed Huisgen's 1,3-dipolar cycloaddition, thus a “click” reaction. According to this strategy, pendent hydroxyl and acrylate groups and atom transfer radical polymerization (ATRP) initiators were successfully attached to PCL. Similarly, amphiphilic graft copolymers were prepared by cycloaddition of an alkyne end-capped poly(ethylene oxide) (PEO) onto the azide substituents of the copolyester. The dependence of the grafting yield on the experimental conditions of the “click” reaction, i.e., temperature, solvent, and catalyst, was investigated. This strategy is very versatile be...