A modified glass reactor for the preparation of linear and star-branched block copolymers via living anionic polymerization

Abstract

A modular high-vacuum system for large-scale anionic polymerization reactions was designed that utilizes mechanical agitation in place of magnetic stirring, Teflon Rotoflo stopcocks in place of glass breakseals, and spherical o-ring joints in place of direct glass seals. A standard reactor body was used, and depending upon reactor design, it was fitted with appropriate reactant ampules, volumetric charging cylinders, etc., to facilitate polymerization, blocking reactions, and linking reactions with minimal effort. To demonstrate the efficacy of the system a number of linear and three-arm star-block copolymers comprised of oligostyrene outer blocks and polybutadiene inner blocks were synthesized. The block copolymers were characterized by narrow molecular weight dispersity, and the star polymers showed greater than 95% linking efficiency. The polybutadiene blocks contained approximately 40% 1,2-enchainment and were exhaustively hydrogenated using H2 and a nickel octoate/triethyl aluminum catalyst. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 151–159, 1997