Monodisperse stereoregular poly(methyl methacrylate) by anionic polymerization. II

Abstract

Abstract Anionic polymerization of poly(methyl methacrylate) in solvating media (THF, glyme, pyridine), using as initiators complexes of the type organic—alkali metal(biphenyl—sodium, biphenyl—lithium), is described, leading to stereoregular and monodisperse polymers. Polymerization is carried out in a vacuum line system, all solvents being previously purified with the same type of complexes used in the polymerization reaction; monomer is purified with benzil—sodium. All transfers are made through sealed ampules. The polymers obtained were fractionated and found to have very narrow molecular weight distributions. All polymers are mainly syndiotactic and their NMR spectra allow the steric composition to be determined, which goes up to 97% syndiotactic. The polymerization can be described by a single parameter governing the probabilities of isotactic and syndiotactic placements, as predicted by the Coleman and Fox theory.