ORBi: Wang Jin-Shan - 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

Reference : Anionic polymerization of (meth)acrylic monomers. 12. Efect of lithium chloride on the s...


	Document type :	Scientific journals : Article
	Discipline(s) :	Physical, chemical, mathematical & earth Sciences : Chemistry Engineering, computing & technology : Materials science & engineering
	To cite this reference:	http://hdl.handle.net/2268/16273

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
Language :	English
Author, co-author :	Wang, Jin-Shan [University of Liège (ULg) > Department of Chemistry > Center for Education and Research on Macromolecules (CERM) > >]
	Jérôme, Robert [University of Liège (ULg) > Department of Chemistry > Center for Education and Research on Macromolecules (CERM) > >]
	Warin, Roger [University of Liège (ULg) > Department of Chemistry > Center for Education and Research on Macromolecules (CERM) > >]
	Teyssié, Philippe [University of Liège (ULg) > Department of Chemistry > Center for Education and Research on Macromolecules (CERM) > >]
Publication date :	25-Oct-1993
Journal title :	Macromolecules
Publisher :	American Chemical Society
Volume :	26
Issue/season :	22
Pages :	5984-5990
Audience :	International
ISSN :	0024-9297
City :	Washington
Country :	DC
Keywords :	[en] anionic polymerization ; (meth)acrylate
Abstract :	[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 units :	Center for Education and Research on Macromolecules (CERM)
Funders :	Elf-Atochem ; Politique Scientifique Fédérale (Belgique) = Belgian Federal Science Policy ; Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS
Target :	Researchers
Permalink :	http://hdl.handle.net/2268/16273
DOI :	10.1021/ma00074a021
Other URL :	http://pubs.acs.org/doi/pdf/10.1021/ma00074a021

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