Chuong Bui

Publications (6)10.69 Total impact

• Article: Dispersion polymerization of methyl acrylate in nonpolar solvent stabilized by block copolymers formed in situ via the RAFT process.

  Lisa Houillot, Chuong Bui, Céline Farcet, Claudine Moire, Jacques-Antoine Raust, Harald Pasch, Maud Save, Bernadette Charleux
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  ABSTRACT: The free-radical dispersion polymerization of methyl acrylate (MA) in isododecane was carried out in the presence of a poly(2-ethylhexyl acrylate) macromolecular RAFT (reversible addition-fragmentation chain transfer) agent bearing a trithiocarbonate reactive group in the middle of the chain (P2EHA-TTC). The presence of the trithiocarbonate function was crucial for the synthesis of monodisperse colloidal poly(methyl acrylate) (PMA) particles stabilized by the P2EHA segments. The hydrodynamic diameters ranged from 100 to 300 nm, using particularly low amounts of the macro(RAFT agent) (1-6 wt % vs. MA) in dispersion polymerizations carried out at 20 wt % solids content. As shown by 2D liquid chromatography, P2EHA-b-PMA or P2EHA-b-PMA-b-P2EHA block copolymers formed in situ at the early stage of the dispersion polymerization due to the reversible transfer process and played the role of particle stabilizer. The glass-transition temperature of the derived polymer films was not affected by the low amount of the chosen macromolecular stabilizer and the mechanical properties were mainly those of PMA, which makes the technique very attractive for coating applications.
  ACS Applied Materials & Interfaces 02/2010; 2(2):434-42. · 4.53 Impact Factor
• Article: Use of a simple surface-active initiator in controlled/living free-radical miniemulsion polymerization under AGET and ARGET ATRP conditions.

  François Stoffelbach, Nebewia Griffete, Chuong Bui, Bernadette Charleux
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  ABSTRACT: This communication describes the first example of the efficient use of a simple amphiphilic molecule as both a surfactant and an initiator in the miniemulsion polymerization of methyl methacrylate under AGET and ARGET ATRP conditions.
  Chemical Communications 11/2008; · 6.17 Impact Factor
• Article: Synthesis of Well-Defined Polyacrylate Particle Dispersions in Organic Medium Using Simultaneous RAFT Polymerization and Self-Assembly of Block Copolymers. A Strong Influence of the Selected Thiocarbonylthio Chain Transfer Agent

  Lisa Houillot, Chuong Bui, Maud Save, Bernadette Charleux
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  ABSTRACT: The RAFT-mediated nonaqueous dispersion polymerization of methyl acrylate in isododecane, a nonsolvent for poly(methyl acrylate), was carried out using two soluble poly(2-ethylhexyl acrylate) macromolecular RAFT agents, containing either a dithiobenzoate reactive function or a trithiocarbonate one. The method produced stable colloidal particles, with hydrodynamic diameters below 100 nm. Using poly(2-ethylhexyl acrylate) with a dithiobenzoate end group, strong rate retardation and poor control over the polymer chains were observed. In contrast, when the trithiocarbonate-functionalized poly(2-ethylhexyl acrylate) was used, the formation of monodisperse micellar aggregates of well-defined self-assembled block copolymers was obtained with fast polymerization rates, irrespective of the RAFT agent concentration. Such differences were explained by the dispersed state of the system rather than by the intrinsic reactivity of the soluble macromolecular RAFT agent.
  08/2007;
• Article: Emulsifier-Free Controlled Free-Radical Emulsion Polymerization of Styrene via RAFT Using Dibenzyltrithiocarbonate as a Chain Transfer Agent and Acrylic Acid as an Ionogenic Comonomer:  Batch and Spontaneous Phase Inversion Processes

  Sébastien Fréal-Saison, Maud Save, Chuong Bui, Bernadette Charleux, Serge Magnet
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  ABSTRACT: Surfactant-free, batch emulsion polymerization of styrene was carried out in the presence of sodium acrylate as a comonomer and dibenzyltrithiocarbonate (DBTTC) as a reversible addition−fragmentation chain transfer (RAFT) agent. Very stable latex was recovered with narrow particle size distribution. Because of the low water-solubility of DBTTC, diffusion of the RAFT agent from the monomer droplets toward the polymer particles was slow, which did not allow a linear increase of molar mass with monomer conversion. However, Mn eventually reached the expected value and the final polymer chains could be extended, when the latex was used as a seed for a second polymerization step. To overcome the slow diffusion of the RAFT agent, a new process was proposed, based on a spontaneous phase inversion mechanism. The method relies upon a first bulk copolymerization of styrene and acrylic acid, followed by neutralization of the carboxylic acid moieties by the addition of a sodium hydroxide solution under gentle stirring, leading to spontaneous phase inversion when a sufficient amount of water has been added. The method was applied to generate stable polymer nuclei, which were further used as a seed for chain extension upon monomer addition.
  11/2006;
• Article: Controlled Free-Radical Polymerization of n-Butyl Acrylate by Reversible Addition−Fragmentation Chain Transfer in the Presence of tert-Butyl Dithiobenzoate. A Kinetic Study

  Elena Chernikova, Andrey Morozov, Ekaterina Leonova, Elizaveta Garina, Vladimir Golubev, Chuong Bui, Bernadette Charleux
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  ABSTRACT: The RAFT polymerization of n-butyl acrylate was studied in the presence of various concentrations of tert-butyl dithiobenzoate (t-BDB) as a chain transfer agent, and various concentrations of AIBN as an initiator at 60 and 90 °C. The polymerizations exhibited the expected features of controlled systems. In particular, the linear increase in number-average molar mass (Mn) with monomer conversion, from very low conversion values, indicated a large apparent chain transfer constant to t-BDB. The kinetic study showed two typical characteristics already observed in RAFT polymerizations of various acrylates:  the existence of an induction period and a strong rate retardation, both enhanced by the increase in t-BDB initial concentration. ESR spectroscopy was applied at 90 °C and revealed the existence of an unexpectedly large concentration of intermediate radicals. The system was examined and discussed considering either the possibility of cross-termination between a propagating macroradical and an intermediate one, with fast fragmentation of the intermediate radicals or the absence of cross-termination but slow fragmentation.
  07/2004;
• Article: Effect of comonomer composition on the controlled free-radical copolymerization of styrene and maleic anhydride by reversible addition–fragmentation chain transfer (RAFT)

  Elena Chernikova, Polina Terpugova, Chuong Bui, Bernadette Charleux
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  ABSTRACT: Controlled free-radical copolymerization of styrene and maleic anhydride was performed in 1,4-dioxane or tetrahydrofurane solution at 60 °C using the RAFT technique. The effect of monomer feed ratio on copolymerization kinetics and on control over molar mass distribution was examined. It was shown that polymerization was faster and quality of control was poorer when the proportion of maleic anhydride in the monomer feed was larger. These features were assigned to a decrease in the chain transfer constant of the polymeric RAFT agent, most probably due to an increase in the apparent rate constant of propagation with the proportion of maleic anhydride.
  Polymer.