REACTIVITY RATIOS AND MICROSTRUCTURE DETERMINATION OF (VINYL-ACETATE) (METHYL-METHACRYLATE) COPOLYMERS

(Vinyl acetate)-(methyl methacrylate) copolymers have been prepared by solution polymerization in benzene at 60-degrees using benzoyl peroxide as initiator. Compositions of the copolymers have been determined using H-1-NMR spectroscopy. Reactivity ratios are r(V) = 0.04, r(M) = 32.2 (Fineman-Ross); r(V) = 0.036 +/- 0.022, r(M) = 25.6 +/- 15.25 (Kelen-Tudos), r(V) = 0.045 +/- 0.02, r(M) = 31.30 +/- 5.58 (RREVM computer program). In C-13(H-1)-NMR spectra, various resonance signals due to carbonyl carbons of V- and M-monomeric units have been assigned to different V- and M-centred triad sequences respectively. Triad sequence distribution obtained from C-13(H-1) NMR spectra are in good agreement with those obtained from Harwood's (terminal model) computer program.