Metal-Containing Initiator Systems. XXX. Selective Initiation of Polymerization with Reduced Nickel/Organic Halides:Cationic Polymerization of Styrene and Isobutyl Vinyl Ether

Abstract

It was found that the binary system composed of reduced nickel and alkyl halides, such as tert-buiyl chloride and carbon tetrachloride, initiates both radical and cationic polymerizations of vinyl monomers. From the effects of inhibitors the polymerization of styrene with this initiator was confirmed to proceed through both radical and cationic intermediates. Nickel halides produced by the reaction of the reduced nickel with the alkyl halides are proposed as the active species for the cationic initiation. Nickel sesquioxide reacted with tert-butyl chloride giving nickel chloride which was active for the initiation of the cationic polymerization of styrene and isobutyl vinyl ether. The binary system composed of nickel carbonyl and carbon tetrachloride, which is known as a radical initiator, also showed cationic activity in the polymerization of isobutyl vinyl ether. The activity of the reduced nickel as a catalyst in the Friedel–Crafts reaction was also investigated. The condensation of benzyl chloride, giving polybenzyl, resulted from heating with the reduced nickel.