POLYMERIZATION OF VINYLCARBAZOLE BY ELECTRON ACCEPTORS .3. INITIATION BY LITHIUM CHLORIDE, BROMIDE AND IODIDE

The polymerization of N-vinylcarbazole is initiated by lithium chloride, bromide and iodide, the activity of the halides increasing in that order. Conversions of over 85 per cent can be attained with lithium iodide at 70°C; chain transfer is substantial. No copolymer is formed with styrene and the proportion of isobutyl vinyl ether incorporated into the copolymer is much smaller than that obtained using cationic initiation. The polymerization is insensitive to oxygen, but is retarded or inhibited by electron donors stronger than the monomer. Polymerization is therefore neither free-radical nor cationic and the initiation is ascribed to increased mesomeric polarization due to association of the N-vinyl lone pair electrons with the lithium cation, the anion exerting a reinforcing effect depending on its nucleophilic power. © 1969.