Nuclear magnetic resonance studies of ionomers. 5. Spectra of poly (methyl methacrylate-co-4-vinyl pyridine), poly (methyl methacrylate-co-2-methyl-5-vinyl pyridine), and their quaternized derivatives

Proton and carbon nuclear magnetic resonance spectra in solution of poly (methyl methacrylate-co-4-vinyl pyridine), poly(methyl methacrylate-co-2-methyl-5-vinyl pyridine), and of their derivatives obtained by quaternization with methyl iodide are presented. The vinyl pyridine structural units content of the samples is ca. 10%. In different solvents, the spectra provide information about the sequence distribution and configuration of the copolymers. A "coisotactic" alternating addition, defined as the probability of finding a methoxy group and a pyridine ring neighboring each other on the same side of the main chain, can be estimated as about 0.5 in both cases. This information arises from the splitting of the aromatic and of the methoxy signals (both in proton and carbon spectra). As expected, quaternization does not affect the copolymer configuration. Heteronuclear-correlated two-dimensional spectra can help in assigning the spectra.