1. Central Laboratory for Polymers, Bulgarian Academy of Sciences, 1040 Sofia, Bulgaria;2. Institute of Macromolecular Compounds of the Academy of Sciences of the U.S.S.R., 199004 Leningrad, U.S.S.R.
Abstract:
The nature of the propagation sites in the anionic polymerization of methoxypolyethyleneglycol methacrylates in the presence of Li counterion has been studied through i.r. spectra of the model compounds, Li derivatives of isobutyric acid esters, (CH3)2CLiCOO(CH2CH2O)nCH3 with n from 1 to 4, and of 2,2,4-trimethylglutaric acid esters. The wavelength of the absorption band of lithioisobutyrates, due to the vibration of the grouping, is independent of the nature of the solvent. This fact has been explained by intramolecular solvation of Li+ by the polyethereal alcoholic residue. The spectra of the metalated trimethylglutarates give evidence of concurrent solvation of Li+ by the alkoxy carbonyl group in the γ-position and the alcoholic residue of the ester group bound to the metalated carbon atom. When the number of ethyleneoxide units in the polyethereal chain is increased, the coordination of Li+ to it prevails over the interaction with the γ-malkoxycarbonyl group.
