Infrared study on the nature of active centers in anionic polymerization

Abstract

The active species structure in alkali metal-initiated polymerization in different media has been investigated, living polydienes of low molecular weight being used as the main objects. An investigation of the IR spectra of living polydienes in the regions from 350 to 650 cm−1 and from 1500 cm−1 to 1700 cm−1 made it possible to find out the influence of the synthesis conditions on the metal-carbon and carbon-carbon double bond stretching frequencies in the active center. In alkali metal-initiated polymerization of hydrocarbon monomers the character of the polymerization process is greatly dependent on the nature of alkali metal and the solvent. By comparison of the spectral data with the microstructure of polymers formed under the same conditions the possible structures of different types of active centers are discussed.