Electronic and steric ligand effects in the radical polymerization of vinyl acetate mediated by beta-ketoiminate complexes of cobalt(II).

Complexes Co[OC(Ph)CHC(Me)NAr](2) [Ar=Ph, 1; o,o'-C(6)H(3)Me(2) (Xyl), 2; p-C(6)H(4)CF(3), 3] are tested in the polymerization of vinyl acetate (VAc) initiated by V-70 (0.8 equiv) at 30 degrees C. Polymerization occurs without any notable induction time yielding PVAc with relatively low polydispersity, but with higher than expected M(n) values, which indicates inefficient trapping processes.

A combined spectroscopic and theoretical study of dibutyltin diacetate and dilaurate in supercritical CO2.

Two organotin catalysts, namely, dibutyltin dilaurate (DBTDL) and dibutyltin diacetate (DBTDA), commonly used in the synthesis of polyurethanes, have been investigated combining vibrational spectroscopic measurements with molecular modeling. The structure and vibrational spectra of the DBTDA molecule have been simulated using density functional theory. Thus, because of the Sn.

Combination of an anionic terminator multifunctional initiator and divergent carbanionic polymerization: application to the synthesis of dendrimer-like polymers and of asymmetric and miktoarm stars.

A new and versatile synthetic strategy that provides access to precisely defined and totally soluble multicarbanionic initiators has been implemented to obtain by divergent growth dendrimer-like samples of polystyrene (PS) (up to the seventh generation) or polybutadiene (PB) (up to the third generation) and also asymmetric and miktoarm stars. This strategy rests on lithium-halide exchange reactions to generate multicarbanionic species and on the design of an original reagent that can concomitantly react with living carbanionic chains/arms to deactivate them and produce multicarbanionic sites after exchange of its bromides against lithium. This reagent, 4,4'-dibromodiphenylethylene (1), functions as a TERminating agent and a Multifunctional INItiator (TERMINI), according to a concept first proposed by Percec in another context.

On the perturbation of the intramolecular H-bond in diols by supercritical CO2: a theoretical and spectroscopic study.

The role played by supercritical carbon dioxide used as a dispersant medium in the synthesis of polyurethane particles has been investigated. High-temperature-high-pressure in situ infrared spectroscopic measurements combined with ab initio calculations were performed to investigate the hydroxyl stretching vibrations of ethylene glycol (EG) and 1,4-butanediol (BD), two monomers commonly used in the field of step growth polymerization. Specific interactions between the diols and CO2 have been put in evidence.

Water soluble polymeric nanogels by xanthate-mediated radical crosslinking copolymerisation.

Branched water-soluble copolymers were obtained by direct radical crosslinking copolymerisation of acrylic acid or acrylamide and N,N'-methylenebisacrylamide at high solid content in the presence of an O-ethylxanthate as a reversible chain transfer agent.

Towards an easy access to amphiphilic rod-coil miktoarm star copolymers.

Water-soluble stimuli-responsive AB2 miktoarm star copolymers were prepared by atom transfer radical polymerisation of styrene followed by chain-end modification, polymerisation of either gamma-benzyl-L-glutamate N-carboxyanhydride or tert-butylacrylate and a final step of hydrolysis.

Synthesis of hybrid dendrimer-star polymers by the RAFT process.

A first generation phosphorus-containing dendrimer with twelve terminal benzyl dithiobenzoate functions was designed and subsequently used as a multifunctional agent to derive hybrid star copolymers consisting of a dendritic core surrounded by twelve polystyrene branches by reversible addition-fragmentation chain transfer (RAFT).