GROUP-TRANSFER POLYMERIZATION - RECENT ADVANCES AND APPLICATIONS

Catalysis of GTP of MMA with nucleophilic anions on crosslinked polystyrene supports was studied. With anion-bound supported catalyst, evidence is presented for formation in solution of ester enolates as reaction intermediates. Study of the cyanide-catalyzed initiation of GTP of MMA by TMSCN, has provided quantitative data for the association constant K(a) for the complexation of cyanide by TMSCN and, by inference, an upper limit for the K(a) for the association of this nucleophilic anion with silyl ketene acetals. The effects of i-propyl- and t-butoxy-silyl analogs of TMSCN on anion-complexation and on initiation and propagation of GTP are discussed. Coordination by hydrogen-bonding of nucleophilic anions to acetonitrile is shown to be the mechanism for ''livingness-enhancement'' of anion-catalyzed GTP at low concentrations of acetonitrile. GTP was used to prepare an ABC triblock dispersant, poly(methacrylic acid)-block-poly(2-phenylethyl methacrylate)-block-poly(ethoxytriethylene glycol methacrylate), and the surface activity of an aqueous solution of the potassum salt was compared with that of other polymer architectures.