Sodium atom induced anionic polymerization in a rotating cryostat.

Sodium atoms have been used to initiate polymerization of homopolymers and block copolymers of styrene, alpha-methylstyrene and methyl methacrylate in a spinning glass cryostat. This represents the first successful use of the metal vapor methodology to prepare polymers in solution, as well as the first use of metal atoms to initiate polymerization. The technique provides for easy batch preparation of high molecular weight polymers. Analysis by size exclusion chromatography, nuclear magnetic resonance and infrared spectroscopies confirm homo- and block polymerizations. The versatility of the system allows for any number of monomers, termination and/or capping reactants to be added to the reaction vessel under the strictest purity conditions. Initiation by metal atoms contrasts with previous work utilizing metal particles and films where the kinetics of initiation are complicated by solvated species and adsorption- desorption processes.