ANIONIC-POLYMERIZATION OF (METH)ACRYLIC MONOMERS .4. EFFECT OF LITHIUM-SALTS AS LIGANDS ON THE LIVING POLYMERIZATION OF METHYL-METHACRYLATE USING MONOFUNCTIONAL INITIATORS

The low-temperature polymerization of methyl methacrylate initiated with monofunctional lithium carbanionic species has been studied in THF and in a 9:1 toluene-THF mixture. Various types of ligand lithium salts have been purposely added to modify the active growth species. Quite interestingly, it has been found that lithium chloride, although not influencing the stereochemistry of the propagation, has an important beneficial effect on the living character of the process. That approach provides for a straightforward high-yield synthesis of PMMA samples displaying a predetermined molecular weight and a very low polydispersity. The LiCl:initiator molar ratio and the polarity of the solvent have been shown to be determinant parameters in the association equilibrium involved in these controls. © 1990, American Chemical Society. All rights reserved.