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See detailControlled processes account for age-related decrease in episodic memory
Vanderaspoilden, Valérie; Adam, Stéphane ULg; Van der Linden, Martial ULg et al

in Acta Psychologica (2007), 125(1), 20-36

A decrease in controlled processes has been proposed to be responsible for age-related episodic memory decline. We used the Process Dissociation Procedure, a method that attempts to estimate the ... [more ▼]

A decrease in controlled processes has been proposed to be responsible for age-related episodic memory decline. We used the Process Dissociation Procedure, a method that attempts to estimate the contribution of controlled and automatic processes to cognitive performance, and entered both estimates in regression analyses. Results indicate that only controlled processes explained a great part of the age-related variance in a word recall task, especially when little environmental support was offered. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailControlled Production of Exopolysaccharides from Enterobacter A47 as a Function of Carbon Source w ith Demonstration of Their Film and Emulsifying Abilities
Freitas, F; Alves, A.V.; Gouveia, A.R. et al

in Applied Biochemistry and Biotechnology (2014), 172

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See detailControlled Production of Exopolysaccharides from Enterobacter A47 as a Function of Carbon Source w ith Demonstration of Their Film and Emulsifying Abilities
Freitas, F; Alves, V.D.; Gouveia, A.R. et al

in Applied Biochemistry and Biotechnology (2013)

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See detailControlled radical (co)polymerization of vinyl monomers using nitrones as precursors of nitroxides
Sciannamea, Valérie; Detrembleur, Christophe ULg; Catala, Jean-Marie et al

Conference (2004, May 27)

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See detailControlled Radical Polymerisation catalysed by rutehnium complexes. Variations on Ru-Cp#
Demonceau, Albert ULg; Delfosse, Sébastien; Guillaume, Bernard et al

in ACS Symposium Series (2002, August)

series of isoelectronic ruthenium-based complexes of the general formula [RuX(Cp#)L2] (Cp# = cyclopentadienyl or cyclopentadienyl derivatives) were synthesized, and their relative catalytic activities ... [more ▼]

series of isoelectronic ruthenium-based complexes of the general formula [RuX(Cp#)L2] (Cp# = cyclopentadienyl or cyclopentadienyl derivatives) were synthesized, and their relative catalytic activities were determined by monitoring the atom transfer radical polymerization of methyl methacrylate, n-butyl acrylate, and styrene. [RuCl(Cp*)(PPh3)2] and [RuCl(Ind)(PPh3)2] were found to be highly efficient catalysts for ATRP, producing polymers with narrow molecular weight distribution (Mw/Mn < 1.2). the following order of increasing efficiency was determined: [RuCl(Cp)(PPh3)2] << [RuCl(ind)(PPh3)2] < [RuCl(Cp*)(PPh3)2]. In sharp contrast, ruthena-carboranes were inefficient for ATRP, demonstrating therefore the prominent role of the Cp# ligand. The effect of the phosphine ligands was also investigated, and additional studies indicated that the release of a phosphine ligand occured prior to the activation of the carbon-halogen bond of both the initiator and polymer growing chain end by the unsaturated ruthenium center. [less ▲]

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See detailControlled radical polymerisation catalysed by ruthenium complexes: Variations on Ru-Cp#
Delfosse, Sébastien; Guillaume, Bernard; Richel, Aurore ULg et al

in Polymer Preprints (2002)

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See detailControlled radical polymerisation of vinyl monomers catalysed by ruthenium N-heterocyclic carbene complexes
Delfosse, Sebastien; Richel, Aurore ULg; Borguet, Yannick ULg et al

in Matyjaszewski, Krzysztof (Ed.) Controlled/living radical polymerization. From synthesis to materials (2005)

N-heterocyclic carbene (NHC)-modified ruthenium catalysts of type [RuCl2(p-cymene)(NHC)] (NHC = substituted 2,3-dihydro-1H-imidazol-2-ylidenes: 1,3-Mes2-4,5-Me2, 1,3-Mes2-4,5-H2, 1,3-Mes2-4,5-Cl2, 1,3-Cy2 ... [more ▼]

N-heterocyclic carbene (NHC)-modified ruthenium catalysts of type [RuCl2(p-cymene)(NHC)] (NHC = substituted 2,3-dihydro-1H-imidazol-2-ylidenes: 1,3-Mes2-4,5-Me2, 1,3-Mes2-4,5-H2, 1,3-Mes2-4,5-Cl2, 1,3-Cy2-4,5-Me2, and 1,3-Cy2-4,5-H2; Mes = mesityl, Cy = cyclohexyl) were prepd. beforehand or in situ by combining the [RuCl2(p-cymene)] dimer with the imidazolium salt in presence of a base (e.g., t-BuOK, Cs2CO3, or Al(OiPr)3). The catalysts were then used in homogeneous atom transfer radical polymns. of Me methacrylate and styrene. The polymn. outcome was studied in dependence of catalyst (substitution pattern) and base. [less ▲]

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See detailControlled radical polymerization catalysed by ruthenium complexes: Variations on Ru-Cp#
Delfosse, Sébastien; Richel, Aurore ULg; Simal, Francois et al

in Matyjaszewski, K. (Ed.) Advances in Controlled/Living Radical Polymerization / ACS Symposium Series 854 (2003)

A series of isoelectronic ruthenium-based complexes of the general formula [RuX(Cp#)L2] (Cp# = cyclopentadienyl or cyclopentadienyl derivatives) were synthesized, and their relative catalytic activities ... [more ▼]

A series of isoelectronic ruthenium-based complexes of the general formula [RuX(Cp#)L2] (Cp# = cyclopentadienyl or cyclopentadienyl derivatives) were synthesized, and their relative catalytic activities were determined by monitoring the atom transfer radical polymerization of methyl methacrylate, n-butyl acrylate, and styrene. [RuCl(Cp*)(PPh3)2] and [RuCl(Ind)(PPh3)2] were found to be highly efficient catalysts for ATRP, producing polymers with narrow molecular weight distribution (Mw/Mn < 1.2). the following order of increasing efficiency was determined: [RuCl(Cp)(PPh3)2] << [RuCl(ind)(PPh3)2] < [RuCl(Cp*)(PPh3)2]. In sharp contrast, ruthena-carboranes were inefficient for ATRP, demonstrating therefore the prominent role of the Cp# ligand. The effect of the phosphine ligands was also investigated, and additional studies indicated that the release of a phosphine ligand occured prior to the activation of the carbon-halogen bond of both the initiator and polymer growing chain end by the unsaturated ruthenium center. [less ▲]

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See detailControlled radical polymerization catalyzed by ruthenium complexes: Variations on Ru-Cp#
Delfosse, Sébastien; Richel, Aurore ULg; Simal, François et al

in Matyjaszewski, Krzysztof (Ed.) ADVANCES IN CONTROLLED/LIVING RADICAL POLYMERIZATION (2003)

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See detailControlled radical polymerization of (meth)acrylates by ATRP with NiBr2(PPh3)2 as catalyst
Moineau, Georges; Minet, Michaël; Dubois, Philippe ULg et al

in Macromolecules (1999), 32(1), 27-35

NiBr2(PPh3)2 has been found to be an efficient catalyst for the ATRP of methyl methacrylate (MMA) and n-butyl acrylate (n-BuA) initiated by an alkyl halide in the absence of any activator (e.g., Lewis ... [more ▼]

NiBr2(PPh3)2 has been found to be an efficient catalyst for the ATRP of methyl methacrylate (MMA) and n-butyl acrylate (n-BuA) initiated by an alkyl halide in the absence of any activator (e.g., Lewis acid) at 85 °C. The molecular weight distribution of the poly(meth)acrylates is narrow (Mw/Mn = 1.1−1.4). However, some side reactions (more likely coupling reactions) are observed at high monomer conversions in the case of n-BuA. An excess of PPh3 has proved to increase the polymerization rate of MMA while preserving the control of the molecular parameters. When the catalyst/initiator molar ratio is too small (e.g., 0.05), the polymerization rate decreases, the polydispersity increases, and the initiation is less efficient. α-Acid and α-hydroxyl end groups have been successfully attached to the chains by using functional initiators, such as 2-bromo-2-methylpropionic acid and 2,2‘,2‘ ‘-tribromoethanol. Reactivity ratios for the MMA/n-BuA comonomer pair have been measured and found to be close to the values observed for a conventional free-radical polymerization. Diethyl meso-2,5-dibromoadipate has been used as a difunctional initiator for the n-BuA polymerization, leading to α,ω-bromo-poly(n-BuA) of narrow molecular weight distribution. Finally, the thermal stability of PMMA is consistent with the lack of termination reactions, while Tg is as high as 125 °C. [less ▲]

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See detailControlled radical polymerization of alkyl methacrylates in the presence of NO/NO2 mixtures
Detrembleur, Christophe ULg; Claes, Michaël; Jérôme, Robert ULg

in Matyjaszewski, Krzysztof (Ed.) Advances in controlled/living radical polymerization (2003)

Radical polymerization of alkyl methacrylates initiated by AIBN is controlled when conducted in the presence of a mixture of NO/NO2. Reaction of alkyl methacrylates with NO/NO2 leads indeed to the monomer ... [more ▼]

Radical polymerization of alkyl methacrylates initiated by AIBN is controlled when conducted in the presence of a mixture of NO/NO2. Reaction of alkyl methacrylates with NO/NO2 leads indeed to the monomer adduct and parent α-nitro, ω-nitroso oligomers, which are precursors of nitroxides, known to control the radical polymerization of alkyl methacrylates, according to a "Nitroxide-Mediated Polymerization" (NMP) mechanism. Although some side reactions may occur with time (increasing polydispersity), polymerization of MMA initiated by AIBN at low temperature (60°C) after bubbling of NO/NO2 is relatively fast, and the molecular weight is dictated by the amount of NO/NO2. Finally, for the first time, copolymerization of MMA with HEMA (10/1; v/v) has been controlled by this mixture of NO and NO2 although the reaction remains very fast (ca. 65% monomer conversion after 5 h at 60°C), which is of prime importance for coating applications. [less ▲]

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See detailControlled radical polymerization of halogenated monomers
Bodart, Vincent; Piette, Yasmine; Detrembleur, Christophe ULg et al

Patent (2012)

Process for the preparation of a halogenated polymer comprising a controlled radical polymerization step of at least one monomer containing at least one halogen-carbon bond performed in the presence of an ... [more ▼]

Process for the preparation of a halogenated polymer comprising a controlled radical polymerization step of at least one monomer containing at least one halogen-carbon bond performed in the presence of an organo-cobalt complex, said polymerization step being further carried out in the presence of at least one ligand. [less ▲]

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See detailControlled radical polymerization of halogenated monomers
Bodart, Vincent; Piette, Yasmine; Detrembleur, Christophe ULg et al

Patent (2012)

Process for the preparation of a halogenated polymer comprising a controlled radical polymerization step of at least one monomer containing at least one halogen-carbon bond, performed in the presence of ... [more ▼]

Process for the preparation of a halogenated polymer comprising a controlled radical polymerization step of at least one monomer containing at least one halogen-carbon bond, performed in the presence of an organo-cobalt complex, said polymerization step being further carried out in non-isotherm conditions. [less ▲]

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See detailControlled radical polymerization of methyl methacrylate initiated by an alkyl halide in the presence of the Wilkinson catalyst
Moineau, Georges; Granel, Claude; Dubois, Philippe ULg et al

in Macromolecules (1998), 31(2), 542-544

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See detailControlled radical polymerization of N-Vinylphthalimide using carboxyl-terminated trithiocarbonate as RAFT agent and preparation of microfibers via electrospinning technique
Chikaoui-Grioune, D.; Aqil, Abdelhafid; Zalfen, Alina M. et al

in Journal of Applied Polymer Science (2010), 117(2), 1005-1012

Reversible addition-fragmentation chain transfer (RAFT) polymerization of N-vinylphthalimide in N,N-dimethylformamide (DMF) solution was carried out using 2-carboxypropan-2-yl dodecyl trithiocarbonate as ... [more ▼]

Reversible addition-fragmentation chain transfer (RAFT) polymerization of N-vinylphthalimide in N,N-dimethylformamide (DMF) solution was carried out using 2-carboxypropan-2-yl dodecyl trithiocarbonate as a reversible chain transfer agent in the presence of 2,2-azobisisobutyronitrile. The molecular weights of the polymers increased linearly with the monomer conversion and the molecular weight distributions were relatively narrow (PDI < 1.2). It is confirmed by chain extension reaction that the polymer prepared via RAFT polymerization can be used as a macro-RAFT agent. The structure of both polymers was characterized and confirmed by size-exclusion chromatography and 1H-NMR techniques. Ultrafine microfibers were prepared by electrospinning of poly(N-vinylphthalimide) in DMF solution. The effects of electrospinning process parameters such as voltage, tip-to-collector distance, and solution concentration on the morphology and the average size of the electrospun fibers were studied. To evaluate the fiber diameters, scanning electron microscope micrographs of the microfibers were performed. [less ▲]

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See detailControlled radical polymerization of styrene by quinone transfer radical polymerization (QTRP)
Caille, Jean-Raphaël; Debuigne, Antoine ULg; Jérôme, Robert ULg

in Macromolecules (2005), 38(1), 27-32

Radical polymerization of styrene falls under control when conducted at 100 degreesC, in the presence of an ortho-quinone, e.g., phenanthrenequinone (PhQ): and a catalytic amount of cobalt(II ... [more ▼]

Radical polymerization of styrene falls under control when conducted at 100 degreesC, in the presence of an ortho-quinone, e.g., phenanthrenequinone (PhQ): and a catalytic amount of cobalt(II) acetylacetonate. Criteria for a controlled chain polymerization are fulfilled at least until 50% of monomer conversion, i.e., molar mass increasing with monomer conversion. molar mass predictable from the styrene/ quinone molar ratio, linear time dependence of ln([M](o)/[M]), and effective resumption of Styrene polymerization by preformed oligopolystyrene. A tentative mechanism is proposed for this new System designated as quinone transfer radical polymerization (QTRP). [less ▲]

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See detailControlled radical polymerization of styrene mediated by the C-phenyl-N-tert-butylnitrone/AIBN pair: Kinetics and electron spin resonance analysis
Sciannamea, Valérie; Catala, Jean-Marie; Jérôme, Robert ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (2007), 45(7), 1219-1235

Kinetics of the free radical polymerization of styrene at 110 degrees C has been investigated in the presence of C-phenyl-N-tert-butylnitrone (PBN) and 2,2'-azobis(isobutyronitrile) (AIBN) after ... [more ▼]

Kinetics of the free radical polymerization of styrene at 110 degrees C has been investigated in the presence of C-phenyl-N-tert-butylnitrone (PBN) and 2,2'-azobis(isobutyronitrile) (AIBN) after prereaction in toluene at 85 degrees C. The effect of the prereaction time and the PBN/AIBN molar ratio on the in situ formation of nitroxides and alkoxyamines (at 85 degrees C), and ultimately on the control of the styrene polymerization at 110 degrees C, has been investigated. As a rule, the styrene radical polymerization is controlled, and the mechanism is one of the classical nitroxide-mediated polymerization. Only one type of nitroxide (low-molecular-mass nitroxide) is formed whatever the prereaction conditions at 85 degrees C, and the equilibrium constant (K) between active and dormant species is 8.7 x 10(-10) mol L-1 at 110 degrees C. At this temperature, the dissociation rate constant (k(d)) is 3.7 x 10(-3) s(-1), the recombination rate constant (k(c)) is 4.3 x 10(6) L mol(-1) s(-1), whereas the activation energy (E-a,E-diss), for the dissociation of the alkoxyamine at the chain-end is similar to 125 kJ mol(-1). Importantly, the propagation rate at 110 degrees C, which does not change significantly with the prereaction time and the PBN/AIBN molar ratio at 85 degrees C, is higher than that for the thermal polymerization at 110 degrees C. This propagation rate directly depends on the equilibrium constant K and on the alkoxyamine and nitroxide concentrations, as well. [less ▲]

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