The structure of poly(N‐vinylcarbazole) obtained with cationic initiators and electron acceptors as catalysts

Abstract

AbstractPoly(N‐vinylcarbazole)s, [poly(l‐(N‐carbazolyl)ethylene)s], (PVCz's) were prepared under various polymerization conditions. The stereoregularities were estimated by means of 13C NMR spectroscopy. Although the stereoregularity of the polymers obtained by BF3O(C2H5)2 was hardly changed by the polymerization temperature, it changed with the solvent polarity from an isotactic‐rich configuration in toluene and CH2Cl2 to a syndiotactic‐rich configuration in nitrobenzene. The 13C NMR spectra of the polymers obtained by organic electron acceptors, support the conclusion that the polymerization by tetracyanoethylene, p‐bromanil, 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone, and tetrachlorophthalic anhydride proceed by a cationic mechanism. In the polymerization of N‐vinylcarbazole (VCz) with maleic anhydride as an electron acceptor, a small amount of copolymer was obtained together with the homopolymer of VCz. Although the structure of the homopolymers is the same as that of the radically obtained polymer, it is considered that the polymer is formed by a cationic mechanism. The polymerizations of VCz by inorganic compounds, such as ferric nitrate, cupric nitrate, cupric bromide, etc., as catalysts are cationic.