Assignment of finely resolved 13C NMR spectra of poly(vinyl alcohol)

13C NMR spectra of three poly(vinyl alcohol)s differing in the stereoregularity (atactic, syndiotactic-rich and isotactic-rich) were determined in DMSO-d6 and D2O. The methylene and methine carbon absorptions including so far unassigned ones (mmmr heptad signals in mm-centered region and all heptad signals in mr-centered region) were completely assigned with hexads and heptads, respectively, and the assignments were quantitatively confirmed for atactic and syndiotactic-rich poly(vinyl alcohol)s. The isotactic-rich polymer showed a discrepancy between the observed and the calculated intensities, assuming the first-order Markov statistics, due to difficulty in determining its polymerization mechanism.