No abstract

A size exclusion chromatography (SEC)‐gradient method is developed allowing poly(n‐butyl acrylate‐stat‐acrylic acid)s to be separated with respect to content of acrylic acid over the ­complete composition range. After setting up the chromatographic method, samples that, according to the amounts of charged monomers, are expected to have identical chemical composition are compared. The chromatograms reveal differences in elution volume, which, by 1H NMR spectroscopy, can be partially traced back to differences in polymer composition. In addition, samples of similar compositions prepared in ­different solvents exhibit differences in chemical composition distribution.

The development of a chromatographic method capable to separate poly(methyl methacrylate-stat-methacrylic acid) samples with methacrylic acid contents of up to 50% by chemical composition is described. For this purpose a gradient ranging from chloroform to dimethylacetamide on a PSS PROTEEMA column was applied. The application of a conventional gradient resulted in severe breakthrough peaks. Therefore, the recently developed concept of SEC gradients was used. No breakthrough peaks were observed, and the peaks corresponding to samples of different content of methacrylic acid were well resolved. A nearly linear relationship between elution volume and methacrylic acid content was observed. The developed method allows determination of the chemical composition distribution of the abovementioned class of polymers.