| Abstract: | 13C-NMR spectroscopy was used in a detailed study of vinyl chloride-vinyl acetate and vinyl chloride-vinyl propionate copolymers. The NMR spectra of the methylene carbon region showed three split peaks whose intensities changed with composition of the copolymers. These peaks were assigned to diad sequences and the observed diad concentrations were in good agreement with the calculated concentrations in terms of the random copolymerization theory. For the methine carbon spectra of vinyl acetate or vinyl propionate units in the copolymers the degree of splitting of the signal was improved by the addition of tris(1,1,1,2,2,3,3-heptafluro-7,7-diemthyl-1,4,6-octanedinata)-praseodymium as a shift reagent. Four peaks assigned to the methine carbon were interpreted in terms of triad sequence distribution and tacticity. |
