Blending the Effectiveness of Anionic Polymerization with the Versatility of RAFT by Use of the Atom Transfer Radical Addition–Fragmentation Technique

Abstract

The efficient conversion of a living anionic polymer chain end to a macrochain transfer agent suitable for reversible addition–fragmentation chain transfer (RAFT) polymerization is reported. Conversion to the macrochain transfer agent efficiency reached as high as 97% by capping the polyanion with alcohol, coupling with α‐bromoisobutryl bromide, followed by atom‐transfer radical addition–fragmentation with bis(thiobenzyl)disulfide to add the chain transfer agent functionality. To our knowledge, this is the most efficient marriage of anionic and reversible addition–fragmentation transfer polymerization reported to date, and can be carried out under common industrial processing conditions. The combination of these polymerization methods broadens the scope of commercially accessible block copolymers by exploiting the advantages of both RAFT and anionic polymerization chemistries.

Linear Block Copolymer Synthesis

“…A more recent work presented by Cochran et al in 2019 claims to be the most efficient combination of living anionic and RAFT polymerization especially when considering industrial applications. In this report, the synthesis of PS under common living anionic polymerization in sec -BuLi was conducted and then underwent end-capping modifications via three options: (a) ethylene oxide, (b) acetal capping, or (c) silyl capping . The resulting hydroxyl-end functionalized PS was then modified by reaction with 2-bromo-2-methylpropanoyl bromide to further react with bis­(thiobenzoyl)­disulfide to form a macro-CTA.…”