Electrochemical Polymerization of N-Vinylcarbazole by Rectangular Wave Form Current

Abstract

The electrolysis of a solution of N-vinylcarbazole and lithium perchlorate in acetic anhydride or acetonitrile by rectangular wave from current (5:1, RWC) resulted in the formation of poly(N-vinylcarbazole) in the anode compartment of a divided cell.
No polymer was obtained when various solvents other than acetic anhydride or acetonitrile were used.
The [η] values of the polymers formed by RWC were higher and their colorations were lighter than those of polymers formed by direct current (DC) under similar conditions.Obviously, the polymerization by RWC would be of overwhelming importance for the preparation ofpolymer ef high molecular weight and of light colored species.
UV and IR spectroscopic studies showed that more ester and acyl groups existed in the polymer formed in an acetic anhydride solution by RWC than by DC, and the structures of polymers formed in an acetonitrile solution were similar to those of the polymersproduced by the usual cationic polymerization, although a small amount of C=C groups existed, in the former polymers.
The presence of very active species in the electrolyzed solution suggested that acyl groups or hydrogen cations, which were produced by electrolysis of acetic anhydride or acetonitrile respectively, initiated the polymerization.
Moreover, it was assumed that the polymerization, initiated by electrolysis RWC proceeds via a cationic mechanism.