Determination of monomer reactivity ratios in radical‐chain copolymerizations at high conversion

Abstract

Abstract The ratios of the logarithmic concentrations of the two co‐monomers, β, for the radical copolymerizations of styrene with methyl methacrylate, vinyl chloride with vinyl acetate, methyl methacrylate with vinyl acetate, acrylic acid with acrylamide, methacrylic acid with methacrylamide and sodium methacrylate with methacrylamide are found to be independent of the degree of conversion. The monomer reactivivity ratios, r 1 and r2 , for these systems are determined by the relation, The values of r 1 and r2 at zero conversion obtained in this work coincide with the literature values; however, as the degree of conversion increases, significant changes in r 1 and r2 are observed. The onset of deviations of r 1 and r2 from their initial values depends on the pair of monomers being studied. The monomer reactivity ratios of the first two of the discussed systems both show positive deviations, but the latter four systems give one positive deviation and another negative.