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Study of the propagation centre in the anionic polymerization of acrylic monomers, 1. Spectroscopic study of methyl 2‐lithioisobutyrate, an initiator for the anionic polymerization of acrylic monomers
Author(s) -
Kříž Jaroslav,
Dybal Jiří,
Vlček Petr,
Janata Miroslav
Publication year - 1994
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1994.021950904
Subject(s) - polymer chemistry , polymerization , anionic addition polymerization , monomer , chemistry , living anionic polymerization , acrylic acid , ionic polymerization , radical polymerization , polymer , organic chemistry
As the simplest model for the propagation centre in the anionic polymerization of methyl methacrylate, the solution of methyl 2‐lithioisobutyrate ( 1 ) in tetrahydrofuran was studied by means of 1 H, 6 Li, 7 Li and 13 C nuclear magnetic resonance (NMR), and Raman spectroscopy at various concentrations and temperatures. A system of equilibria of differently solvated dimeric, tetrameric and two isomeric trimeric aggregates was found and their thermodynamic constants were established. On the basis of the analysis of NMR chemical shifts, heteronuclear nuclear Overhauser effect correlation spectroscopy (NOESY) spectra and relaxation data, structures of the aggregates are suggested. The kinetics of the exchange between the aggregates and the lifetime of individual aggregates was established. The results suggest that the aggregation can interfere with initiation in the early steps of anionic polymerization of acrylics.