Efficient access to multi-arm star block copolymers by a combination of ATRP and RAFT-HDA click chemistry

A study was conducted to provide an access route to diene-functionalized polymers through atom transfer radical polymerization (ATRP) and their utilization in the reversible addition-fragmentation chain transfer (RAFT)-hetero-Diels-Alder (HDA) protocol, which opened the possibilities of controlled radical polymerization (CRP) techniques to access complex architectures. 1,8-Diazabicyclo[5.4.0]undec-7-ene, trans,trans-2,4-hexadiene-1-ol, succinic anhydride, N,N-iisopropylethylamine, zinc chloride, and 1,10-azobis(cyclohexanecarbonitrile) were used for the study as received. Preparative GPC analysis was also carried out with CHCl3 as the solvent at a flow rate of 10 mL min-1 at room temperature. It was observed that the bromine end groups from the ATRP mechanism provided a synthetic handle for post-polymerization modifications. It was concluded that the RAFT-HDA conjugation approach was suitable for the tailor-made synthesis of complex macromolecular architectures.