Atom transfer radical polymerization of styrene initiated by polychloroalkanes and catalyzed by CuCl/2,2?-bipyridine: A kinetic and mechanistic study

Abstract

A series of polychloroalkanes, known as telogen agents for redox telomerization, were used as initiators for atom transfer radical polymerization (ATRP) of styrene using the heterogeneous CuCl/2,2′-bipyridine catalyst. In copper-catalyzed redox telomerization, the reactivity of RCCl3-type telogens is strongly influenced by the nature of the R group. In ATRP, the 2,2′-bipyridine ligand levels the activity of the catalytic system in such a way that all 1,1,1-trichloroalkanes are efficient initiators in ATRP, whatever the R group. The nature of this substituent influences the overall rate of polymerization through both the number of active sites per chain and the [Cu (I)]/[Cu (II)] ratio. By the combining of several analytical techniques, it is proved that some polychloroalkanes such as CCl3CO2CH3, CCl3CF3, or CCl4 are bifunctional initiators. Finally, a general mechanism of initiation is proposed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2933–2947, 1998