Anionic polymerization of (meth)acrylic monomers. 12. Efect of lithium chloride on the stereochemistry on the anionic polymerization of methyl methacrylate in THF and in a 9/1 toluene/THF mixture
[en] The effect of LiCl on the stereochemistry of the anionic polymerization of methyl methacrylate in the presence of a lithium counterion at -78-degrees-C in THF and in a 9/1 toluene/THF mixture, has been studied by C-13 and H-1 NMR spectroscopy. It has been found that LiCl has an important effect on the E/Z ratio of the living chain ends in THF, in contrast to the main-chain tacticity. In contrast, LiCl has a significant influence on the stereoregularity of the anionic polymerization of MMA in a 9/1 toluene/THF mixture. When the LiCl/initiator molar ratio is increased, the syndiotactic placements (rr) are favored at the expense of the isotactic ones (mm). This effect can be accounted for by a multistate propagating mechanism controlled by association/complexation equilibria among associated, nonassociated, and LiCl-complexed species. These association/complexation equilbria, which were originally proposed by Muller, appear to have a decisive effect not only on the livingness (molecular weight distribution (MWD)) but also on the stereochemistry of the anionic polymerization of MMA in a 9/1 toluene/THF mixture at -78-degrees-C, confirming the involvement of the ligand in propagation control.
Research Center/Unit :
Center for Education and Research on Macromolecules (CERM)
Disciplines :
Chemistry Materials science & engineering
Author, co-author :
Wang, Jin-Shan; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Jérôme, Robert ; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Warin, Roger; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Teyssié, Philippe ; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Language :
English
Title :
Anionic polymerization of (meth)acrylic monomers. 12. Efect of lithium chloride on the stereochemistry on the anionic polymerization of methyl methacrylate in THF and in a 9/1 toluene/THF mixture
Publication date :
25 October 1993
Journal title :
Macromolecules
ISSN :
0024-9297
eISSN :
1520-5835
Publisher :
American Chemical Society, Washington, United States - District of Columbia
Elf Atochem BELSPO - SPP Politique scientifique - Service Public Fédéral de Programmation Politique scientifique F.R.S.-FNRS - Fonds de la Recherche Scientifique
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Bibliography
Teyssié, Ph.; Jérôme, R.; Ouhadi, T.; Fayt, R. U.S. Patent 4,461,874, 1984.
Varshney, S. K.; Hautekeer, J. P.; Fayt, R.; Jérôme, R.; Teyssié, Ph. Macromolecules 1990, 23, 2618.
Hautekeer, J. P.; Varshney, S. K.; Fayt, R.; Jacobs, C.; Jérôme, R.; Teyssié, Ph. Macromolecules 1990, 23, 3893.
Varshney, S. K.; Jacobs, C.; Hautekeer, J. P.; Bayard, Ph.; Jérôme, R.; Fayt, R.; Teyssié, Ph. Macromolecules 1991, 24, 4997.
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