Metal‐containing initiator systems. V. Radical and cationic polymerizations with initiator systems of reduced nickel and chlorosilanes

Abstract

AbstractThe polymerizations of methyl methacrylate, styrene, and isobutyl vinyl ether with the binary systems of reduced nickel and chlorosilanes [(CH3)nSiCl4−n, n = 0–3] have been investigated. It was found that these systems could act as both radical and cationic initiators, depending on the nature of vinyl monomers used. The kinetic investigations indicated that methyl methacrylate polymerized via a radical mechanism, and the initiating activity of chlorosilanes decreased in the following order: SiCl4 > CH3SiCl3 > (CH3)2SiCl2 > (CH3)3SiCl ≃ 0. Cationic initiations were observed in the polymerizations of styrene and isobutyl vinyl ether. In the latter case, the activity of chlorosilanes was in the following order: (CH3)3SiCl > (CH3)2SiCl2 > CH3SiCl3 ≃ SiCl4. From the results obtained, a possible mechanism of selective initiation with these systems is proposed and discussed.