The potential of 1H NMR spectroscopy for studying the kinetics and mechanism of controlled radical polymerization with reversible chain transfer

Abstract

The potential of 1H NMR spectroscopy for determining the constants of chain transfer to a symmetric bifunctional agent of reversible chain transfer and for studying the changes in the current concentrations of the initial and final agents formed during the replacement of one leaving group with a polymer (oligomeric) radical of the agents of reversible chain transfer during the homopolymerization of N-vinyl succinimide, the homopolymerization of vinyl acetate, and the copolymerization of 4-vinylpyridine and tert-butyl acrylate in the presence S,S-dibenzyltrithiocarbonate is studied. The correct calculation of the constants of chain transfer is shown to be possible only during agreement of the studied system with the taken scheme of polymerization with reversible chain transfer, a minimum contribution of side reactions, and signal separation that is sufficient for the quantitative analysis of initial and polymer (monosubstituted) agents of reversible chain transfer in the 1H NMR spectra. The lower limit of the constants of transfer to the polymer agents of reversible chain transfer is estimated, and the great efficiency of these agents in comparison to that of the initial low-molecular-mass ones is directly confirmed. A complex of necessary investigations to study any new polymerization system where the controlled radical homoand copolymerization with reversible chain transfer in the presence of symmetric trithiocarbonates occurs is performed.