Controlled RAFT Polymerization in a Continuous Flow Microreactor

Controlled radical polymerization using the reversible addition-fragmentation chain transfer approach (RAFT) was successfully conducted under continuous flow processing conditions, provided that steel tubing was used to prevent quenching of the radical process by oxygen. A series of different monomers, including acrylamides, acrylates, and vinyl acetate, were polymerized to high conversions (between 80 and 100%) at temperatures between 70 and 100 degrees C using various initiators, solvents, and RAFT agents. Low dispersities, typically between 1.15-1.20, and average molecular weights similar to those of batch RAFT polymerizations were obtained. The methodology provides a facile, alternative scale-up route to conventional batch polymerization, which can be challenging because of the oxygen-sensitive nature of the RAFT process.