Determination of monomer reactivity ratios in copolymerizations with N‐vinylpyrrolidone by means of high‐speed liquid chromatography

Abstract High‐speed liquid chromatography was applied to the studies of the polymerization of N‐vinylpyrrolidone and its copolymerizations with vinyl acetate, glycidyl methacrylate and methyl methacrylate. The conversion was calculated from the decrease in peak‐height in the chromatogram of the monomer. A small change in the amount of monomer was closely determined by using o‐diphenyl benzene (o‐terphenyl) as an internal standard. The calculations of the monomer reactivity ratios gave concordant results with those reported earlier. The obtained copolymer compositions agreed with the data by elementary analysis. The application of high‐speed liquid chromatography to the determination of copolymerization reactivity ratios was thus found to be advantageous for saving time. The monomer reactivity ratio can be determined without the complicated processings such as separating, drying and analysing the copolymers.