Synthesis of PS-b-PPOA-b-PS triblock copolymer via sequential free radical polymerization and ATRP

Abstract

A novel ABA triblock copolymer comprising double‐bond‐containing poly(phenoxyallene) (PPOA) and polystyrene (PS) segments was synthesized by sequential conventional free radical polymerization and atom transfer radical polymerization (ATRP) via the site transformation strategy. A new bifunctional initiator containing azo and Br‐containing ATRP initiating groups was prepared using 2‐bromopropionyl chloride, hydroquinone, and 4,4′‐azobis(4‐cyanopentanoic acid) as starting materials. Conventional free radical homopolymerization of phenoxyallene with cumulated double bond was performed in toluene to provide a polyallene‐based macroinitiator bearing ATRP initiating groups at both ends, which is stable under UV irradiation and free radical circumstances. PS‐b‐PPOA‐b‐PS triblock copolymer was then obtained by bulk ATRP of styrene initiated by PPOA‐based macroinitiator. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1366–1372

Synthesis of double-bond-containing diblock copolymers via RAFT polymerization

“…Our group has reported the synthesis of diblock copolymers using phenoxyallene (POA) and common vinyl monomers via the site transformation strategy by the combination of conventional free radical polymerization of allene monomer and ATRP of vinyl monomer. 26,27 However, these block copolymers are certainly not controlled and their molecular weight distributions are very broad. As it is well known, RAFT polymerization is a metal-free powerful tool for the preparation of well-defined functional polymers because of its mild reaction conditions and high tolerance.…”