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Radical Polymerization Techniques (radical + polymerization_techniques)
Selected AbstractsHeteroarm H-shaped terpolymers through the combination of the Diels,Alder reaction and controlled/living radical polymerization techniquesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2006Hakan Durmaz Abstract Heteroarm H-shaped terpolymers (PS)(PtBA),PEO,(PtBA)(PS) and (PS)(PtBA),PPO,(PtBA)(PS) [where PS is polystyrene, PtBA is poly(tert -butyl acrylate), PEO is poly(ethylene oxide), and PPO is poly(propylene oxide)], containing PEO or PPO as a backbone and PS and PtBA as side arms, were prepared via the combination of the Diels,Alder reaction and atom transfer radical and nitroxide-mediated radical polymerization routes. Commercially available PEO or PPO containing bismaleimide end groups was reacted with a compound having an anthracene functionality, succinic acid anthracen-9-yl methyl ester 3-(2-bromo-2-methylpropionyloxy)-2-methyl-2-[2-phenyl-2-(2,2,6,6-tetramethylpiperidin-1-yloxy)ethoxycarbonyl]propyl ester, with a Diels,Alder reaction strategy. The obtained macroinitiator with tertiary bromide and 2,2,6,6-tetramethylpiperidin-1-oxy functional end groups was used subsequently in the atom transfer radical polymerization of tert -butyl acrylate and in the nitroxide-mediated free-radical polymerization of styrene to produce heteroarm H-shaped terpolymers with moderately low molecular weight distributions (<1.31). The polymers were characterized with 1H NMR, ultraviolet, gel permeation chromatography, and differential scanning calorimetry. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3947,3957, 2006 [source] Macromolecular design via reversible addition,fragmentation chain transfer (RAFT)/xanthates (MADIX) polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2005Sébastien Perrier Abstract Among the living radical polymerization techniques, reversible addition,fragmentation chain transfer (RAFT) and macromolecular design via the interchange of xanthates (MADIX) polymerizations appear to be the most versatile processes in terms of the reaction conditions, the variety of monomers for which polymerization can be controlled, tolerance to functionalities, and the range of polymeric architectures that can be produced. This review highlights the progress made in RAFT/MADIX polymerization since the first report in 1998. It addresses, in turn, the mechanism and kinetics of the process, examines the various components of the system, including the synthesis paths of the thiocarbonyl-thio compounds used as chain-transfer agents, and the conditions of polymerization, and gives an account of the wide range of monomers that have been successfully polymerized to date, as well as the various polymeric architectures that have been produced. In the last section, this review describes the future challenges that the process will face and shows its opening to a wider scientific community as a synthetic tool for the production of functional macromolecules and materials. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43:5347,5393, 2005 [source] Living/controlled copolymerization of acrylates with nonactivated alkenesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 24 2004Shengsheng Liu Abstract The living/controlled copolymerization of methyl acrylate with 1-alkenes and norbornene derivatives through several radical polymerization techniques has been achieved. These techniques include atom transfer radical polymerization, reversible addition,fragmentation transfer polymerization, nitroxide-mediated polymerization, and degenerative transfer polymerization. These systems display many of the characteristics of a living polymerization process: the molecular weight increases linearly with the overall conversion, but the polydispersity remains low. Novel block copolymers have been synthesized through the sequential addition of monomers or chain extension. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6175,6192, 2004 [source] Synthesis of proton-conducting membranes by the utilization of preirradiation grafting and atom transfer radical polymerization techniquesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2002Svante Holmberg Abstract The atom transfer radical polymerization (ATRP) of styrene onto poly(vinylidene fluoride)- graft -poly(vinylbenzyl chloride) (PVDF- g -PVBC) membranes was investigated. Novel membranes were designed for fuel-cell applications. The benzyl chloride groups in the PVDF- g -PVBC membranes functioned as initiators, and a Cu-based catalytic system with the general formula Cu(n)Xn/ligand [where X is Cl or Br and the ligand is 2,2,-bipyridyl (bpy)] was employed for the ATRP. In addition, 10 vol % dimethylformamide was added for increased solubility of the catalyst complex in styrene. The system was homogeneous, except for the membrane, when the initiator/copper halide/ligand/monomer molar ratio was 1/1/3/500. As anticipated, the fastest polymerization rate of styrene was observed with the copper bromide/bpy-based catalyst system. The reaction rate was strongly temperature-dependent within the studied temperature interval of 100,130 °C. The degree of grafting increased linearly with time, thereby indicating first-order kinetics, regardless of the polymerization temperature. Furthermore, 120 °C was the maximum polymerization temperature that could be used in practice because the membrane structure was destroyed at higher temperatures. The degree of styrene grafting reached 400% after 3 h at 120 °C. Such a high degree of grafting could not be reached with conventional uncontrolled radiation-induced grafting methods because of termination reactions. On the basis of an Arrhenius plot, the activation energy for the homogeneous ATRP of styrene was 217 kJ/mol. The prepared membranes became proton-conducting after sulfonation of the polystyrene grafts. The highest conductivity measured for the prepared membranes was 70 mS/cm, which is comparable to the values normally measured for commercial Nafion membranes. The scanning electron microscopy/energy-dispersive X-ray results showed that the membranes had to be grafted through the matrix with both PVBC and polystyrene to become proton-conducting after sulfonation. In addition, PVDF- g -[PVBC- g -(styrene- block - tert -butyl acrylate)] membranes were also synthesized by ATRP. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 591,600, 2002; DOI 10.1002/pola.10146 [source] Solution self-assembly of tailor-made macromolecular building blocks prepared by controlled radical polymerization techniquesPOLYMER INTERNATIONAL, Issue 9 2006Jean-François Lutz Abstract This review describes the preparation of colloidal aggregates (spherical micelles, cylindrical micelles, polymer vesicles, multicompartment micelles, polyion complexes, schizophrenic micelles) using bottom-up self-assembly approaches. In particular, it focuses primarily on the self-organization of well-defined macromolecular building blocks (macrosurfactants, polysoaps, polyelectrolytes) synthesized by controlled radical polymerization techniques such as atom transfer radical polymerization, reversible addition fragmentation transfer polymerization and nitroxide-mediated polymerization. The goal of this review is to highlight that these versatile techniques of polymer synthesis allow the preparation of unprecedented nanostructures in dilute solutions. Copyright © 2006 Society of Chemical Industry [source] | ||||||||||