Carbon‐13 nuclear magnetic resonance studies of poly(N‐vinylcarbazole)

Abstract

AbstractThe 13C NMR spectra of poly(N‐vinylcarbazole), [poly(1‐(N‐carbazolyl)ethylene)], prepared under various polymerization conditions were measured at 25,03 MHz in 1,4‐dioxane solution. The spectra were assigned by the chemical shifts and T1 measurements of the polymers and N‐ethylcarbazole as a model compound. The absorption of methylene and methine carbons varied by the polymerization methods. It was tentatively presumed that the polymers obtained by radical polymerization had syndiotactic‐rich structures and the polymers prepared with BF3O(C2H5)2 isotactic‐rich structures. The hindered internal rotation of the bulky carbazolyl group at the main chain of poly(N‐vinylcarbazole) was also observed. The 13C NMR spectra indicated that the polymerization of N‐vinylcarbazole with nitroethane proceeded by a radical mechanism while that with chloranil, (2,3,5,6‐tetrachloro‐1,4‐benzoquinone), proceeded by a cationic mechanism.