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Bernadette Charleux - One of the best experts on this subject based on the ideXlab platform.
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amphiphilic block copolymer nano fibers via raft mediated polymerization in aqueous Dispersed System
Chemical Communications, 2010Co-Authors: Bernadette Charleux, Stephanie Boisse, Jutta Rieger, Khaled Belal, Aurelie Dicicco, Patricia BeaunierAbstract:Self-assembled block copolymer nanofibers are attractive materials for multiple applications. We propose here a novel, very simple and straightforward method to prepare polymeric nanofibers at high solids contents directly in water. It is based on an aqueous emulsion polymerization process performed under living radical polymerization conditions, using the RAFT method.
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atom transfer radical polymerization of n butyl methacrylate in an aqueous Dispersed System a miniemulsion approach
Journal of Polymer Science Part A, 2000Co-Authors: Krzysztof Matyjaszewski, Jian Qiu, Nicolay V Tsarevsky, Bernadette CharleuxAbstract:Ultrasonication was applied in combination with a hydrophobe for the copper-mediated atom transfer radical polymerization of n-butyl methacrylate in an aqueous Dispersed System. A controlled polymerization was successfully achieved, as demonstrated by a linear correlation between the molecular weights and the monomer conversion. The polydispersities of the polymers were small (weight-average molecular weight/number-average molecular weight < 1.5). The influence of several factors, including ultrasonication, the amount of the surfactant, and the nature of the initiator, on the polymerization kinetics, molecular weight, and particle size was studied. The polymerization rate and molecular weights were independent of the number of particles and only depended on the atom transfer equilibrium. The final particle size, however, was a function of all the parameters.
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mechanistic aspect of reverse atom transfer radical polymerization of n butyl methacrylate in aqueous Dispersed System
Macromolecules, 2000Co-Authors: Jian Qiu, Bernadette Charleux, Tomislav Pintauer, Scott G Gaynor, Krzysztof Matyjaszewski, Jean-pierre VaironAbstract:Reverse atom transfer radical polymerization (ATRP) of n-butyl methacrylate was conducted in an aqueous Dispersed System. Using a water-soluble initiator (V-50), a nonionic surfactant (Brij 98), and a hydrophobic ligand (dNbpy) to complex a copper halide, polymers with relatively well controlled molar masses and low polydispersities were obtained. Stable latexes with particle diameters within 150−300 nm were formed. Kinetic studies were performed under various experimental conditions. The influence of the concentrations of the catalyst, the surfactant, and the initiator as well as the temperature on the polymerization rate, molecular weight, and particle size was investigated. Because of the lack of high molecular weight polymer during the early polymerization stage, reverse ATRP in the aqueous Dispersed System presumably has a different “nucleation” mechanism from that of a conventional emulsion polymerization. In addition, fast decomposition of the initiator prevents the continuous entry of radicals int...
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polystyrene block poly butyl acrylate and polystyrene block poly butyl acrylate co styrene block copolymers prepared via controlled free radical miniemulsion polymerization using degenerative iodine transfer
Macromolecular Rapid Communications, 2000Co-Authors: Celine Farcet, Jean-pierre Vairon, Rosangela Pirri, Muriel Lansalot, Bernadette CharleuxAbstract:Polystyrene-block-poly(butyl acrylate) and polystyrene-block-poly[(butyl acrylate)-co-styrene] block copolymers were prepared in an aqueous Dispersed System via controlled free-radical miniemulsion polymerization using degenerative iodine transfer. The first step is batch miniemulsion polymerization of styrene in the presence of C 6 F 13 I as transfer agent. The second step consists of the addition of butyl acrylate to this seed latex, either in one shot or continuously. The addition was started before the consumption of styrene was complete in order to perform a copolymerization reaction able to moderate the rate of propagation in the butyl acrylate polymerization step and, therefore, to favor the transfer reaction. Kinetics of polymerization and control of the molar masses were examined according to the experimental conditions and particularly to the rate of butyl acrylate addition. The formed block copolymers were analyzed by size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR). formula chim. Evolution of M n with conversion for the second block (straight line: theoretical M n )
Jean-pierre Vairon - One of the best experts on this subject based on the ideXlab platform.
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mechanistic aspect of reverse atom transfer radical polymerization of n butyl methacrylate in aqueous Dispersed System
Macromolecules, 2000Co-Authors: Jian Qiu, Bernadette Charleux, Tomislav Pintauer, Scott G Gaynor, Krzysztof Matyjaszewski, Jean-pierre VaironAbstract:Reverse atom transfer radical polymerization (ATRP) of n-butyl methacrylate was conducted in an aqueous Dispersed System. Using a water-soluble initiator (V-50), a nonionic surfactant (Brij 98), and a hydrophobic ligand (dNbpy) to complex a copper halide, polymers with relatively well controlled molar masses and low polydispersities were obtained. Stable latexes with particle diameters within 150−300 nm were formed. Kinetic studies were performed under various experimental conditions. The influence of the concentrations of the catalyst, the surfactant, and the initiator as well as the temperature on the polymerization rate, molecular weight, and particle size was investigated. Because of the lack of high molecular weight polymer during the early polymerization stage, reverse ATRP in the aqueous Dispersed System presumably has a different “nucleation” mechanism from that of a conventional emulsion polymerization. In addition, fast decomposition of the initiator prevents the continuous entry of radicals int...
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polystyrene block poly butyl acrylate and polystyrene block poly butyl acrylate co styrene block copolymers prepared via controlled free radical miniemulsion polymerization using degenerative iodine transfer
Macromolecular Rapid Communications, 2000Co-Authors: Celine Farcet, Jean-pierre Vairon, Rosangela Pirri, Muriel Lansalot, Bernadette CharleuxAbstract:Polystyrene-block-poly(butyl acrylate) and polystyrene-block-poly[(butyl acrylate)-co-styrene] block copolymers were prepared in an aqueous Dispersed System via controlled free-radical miniemulsion polymerization using degenerative iodine transfer. The first step is batch miniemulsion polymerization of styrene in the presence of C 6 F 13 I as transfer agent. The second step consists of the addition of butyl acrylate to this seed latex, either in one shot or continuously. The addition was started before the consumption of styrene was complete in order to perform a copolymerization reaction able to moderate the rate of propagation in the butyl acrylate polymerization step and, therefore, to favor the transfer reaction. Kinetics of polymerization and control of the molar masses were examined according to the experimental conditions and particularly to the rate of butyl acrylate addition. The formed block copolymers were analyzed by size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR). formula chim. Evolution of M n with conversion for the second block (straight line: theoretical M n )
Muriel Lansalot - One of the best experts on this subject based on the ideXlab platform.
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use of a poly ethylene oxide macroraft agent as both a stabilizer and a control agent in styrene polymerization in aqueous Dispersed System
Macromolecules, 2009Co-Authors: Martins Dos A Santos, Le T Bris, C Graillat, Franck Dagosto, Muriel LansalotAbstract:A poly(ethylene oxide)-based macromolecular agent for reversible addition-fragmentation chain transfer (PEO-RAFT, 2 000 g·mol−1) was synthesized and used as a stabilizer and a control agent in the miniemulsion polymerization of styrene. Using 2,2′-azobis(isobutyronitrile) as initiator, stable polystyrene (PS) particles sterically stabilized by the PEO segments were obtained with almost complete conversion after 22 h. Molar masses increased linearly with conversion although rather broad molar mass distributions were obtained due to the presence of several populations of PEO-b-PS block copolymers. However, dynamic light scattering analyses showed a significant increase in particle diameter with conversion and the ratio of the number of particles to the number of droplets (Np/Nd) was thus lower than one indicating that the System did not follow a true miniemulsion process. Transmission electron microscopy additionally revealed the presence of holes inside the formed particles suggesting that block copolymer ...
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polystyrene block poly butyl acrylate and polystyrene block poly butyl acrylate co styrene block copolymers prepared via controlled free radical miniemulsion polymerization using degenerative iodine transfer
Macromolecular Rapid Communications, 2000Co-Authors: Celine Farcet, Jean-pierre Vairon, Rosangela Pirri, Muriel Lansalot, Bernadette CharleuxAbstract:Polystyrene-block-poly(butyl acrylate) and polystyrene-block-poly[(butyl acrylate)-co-styrene] block copolymers were prepared in an aqueous Dispersed System via controlled free-radical miniemulsion polymerization using degenerative iodine transfer. The first step is batch miniemulsion polymerization of styrene in the presence of C 6 F 13 I as transfer agent. The second step consists of the addition of butyl acrylate to this seed latex, either in one shot or continuously. The addition was started before the consumption of styrene was complete in order to perform a copolymerization reaction able to moderate the rate of propagation in the butyl acrylate polymerization step and, therefore, to favor the transfer reaction. Kinetics of polymerization and control of the molar masses were examined according to the experimental conditions and particularly to the rate of butyl acrylate addition. The formed block copolymers were analyzed by size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR). formula chim. Evolution of M n with conversion for the second block (straight line: theoretical M n )
Celine Farcet - One of the best experts on this subject based on the ideXlab platform.
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polystyrene block poly butyl acrylate and polystyrene block poly butyl acrylate co styrene block copolymers prepared via controlled free radical miniemulsion polymerization using degenerative iodine transfer
Macromolecular Rapid Communications, 2000Co-Authors: Celine Farcet, Jean-pierre Vairon, Rosangela Pirri, Muriel Lansalot, Bernadette CharleuxAbstract:Polystyrene-block-poly(butyl acrylate) and polystyrene-block-poly[(butyl acrylate)-co-styrene] block copolymers were prepared in an aqueous Dispersed System via controlled free-radical miniemulsion polymerization using degenerative iodine transfer. The first step is batch miniemulsion polymerization of styrene in the presence of C 6 F 13 I as transfer agent. The second step consists of the addition of butyl acrylate to this seed latex, either in one shot or continuously. The addition was started before the consumption of styrene was complete in order to perform a copolymerization reaction able to moderate the rate of propagation in the butyl acrylate polymerization step and, therefore, to favor the transfer reaction. Kinetics of polymerization and control of the molar masses were examined according to the experimental conditions and particularly to the rate of butyl acrylate addition. The formed block copolymers were analyzed by size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR). formula chim. Evolution of M n with conversion for the second block (straight line: theoretical M n )
Rosangela Pirri - One of the best experts on this subject based on the ideXlab platform.
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polystyrene block poly butyl acrylate and polystyrene block poly butyl acrylate co styrene block copolymers prepared via controlled free radical miniemulsion polymerization using degenerative iodine transfer
Macromolecular Rapid Communications, 2000Co-Authors: Celine Farcet, Jean-pierre Vairon, Rosangela Pirri, Muriel Lansalot, Bernadette CharleuxAbstract:Polystyrene-block-poly(butyl acrylate) and polystyrene-block-poly[(butyl acrylate)-co-styrene] block copolymers were prepared in an aqueous Dispersed System via controlled free-radical miniemulsion polymerization using degenerative iodine transfer. The first step is batch miniemulsion polymerization of styrene in the presence of C 6 F 13 I as transfer agent. The second step consists of the addition of butyl acrylate to this seed latex, either in one shot or continuously. The addition was started before the consumption of styrene was complete in order to perform a copolymerization reaction able to moderate the rate of propagation in the butyl acrylate polymerization step and, therefore, to favor the transfer reaction. Kinetics of polymerization and control of the molar masses were examined according to the experimental conditions and particularly to the rate of butyl acrylate addition. The formed block copolymers were analyzed by size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR). formula chim. Evolution of M n with conversion for the second block (straight line: theoretical M n )