Group-transfer polymerization: Recent advances and applications

Abstract: Catalysis of GTP of MMA with nucleophilic anions on cross-linked 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.