Living Anionic Polymerization in Continuous Flow: Facilitated Synthesis of High-Molecular Weight Poly(2-vinylpyridine) and Polystyrene

Abstract

We describe the living anionic polymerization of 2-vinylpyridine (2VP) and styrene (S) in continuous flow, comparing two micromixing devices with different mixing principles. The use of a continuous flow setup reduces the experimental effort for living anionic polymerizations significantly, compared to a conventional batch system. By adjusting the ratio of the flow rates of the monomer and initiator solutions a variety of different molecular weights can be rapidly synthesized within several minutes, using one setup. Additionally, a comparison of the influence of the two different mixing devices—an interdigital micromixer (SIMM-V2) leading to laminar mixing and a tangential four-way jet mixing device leading to a turbulent mixing pattern—has been achieved. Both setups allow living anionic polymerization in polar solvents at room temperature with full monomer conversion within seconds and yield polymers with narrowly distributed molecular weights. A maximum Mn of approximately 149,000 g mol–1 (PS-9, PDI = 1.04) for PS and 96,000 g mol–1 for P2VP (P2VP-15, PDI = 1.05) was obtained. Clearly, the turbulent four-way jet mixing device led to lower polydispersity than the laminar mixing device. All polymers were characterized by 1H NMR spectroscopy and size exclusion chromatography (SEC).