Transfer Polymerization (transfer + polymerization)

Distribution by Scientific Domains

Kinds of Transfer Polymerization

  • addition fragmentation chain transfer polymerization
  • chain transfer polymerization
  • fragmentation chain transfer polymerization
  • reversible addition fragmentation chain transfer polymerization


  • Selected Abstracts


    Synthesis and Structure of Aminopyridinato-Stabilized Yttrium and Lanthanum Amides and Their Reactivity towards Alkylaluminium Compounds

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2009
    Christian Dring
    Abstract A series of aminopyridinato-stabilized (amido)lanthanide complexes has been synthesized and characterized. The bulky aminopyridines (2,6-diisopropylphenyl)[6-(2,4,6-triisopropylphenyl)pyridin-2-yl]amine (1a) and [6-(2,4,6-triisopropylphenyl)pyridin-2-yl](2,4,6-trimethylphenyl)amine (1b) were introduced by amine elimination reaction with [Ln{N(SiHMe2)2}3(thf)2] (Ln = Y, La, thf = tetrahydrofuran, Me = methyl) to obtain the corresponding mono(aminopyridinato) complexes. Single-crystal X-ray analyses were carried out for the yttrium derivatives. The complexes are not able to undergo coordinative chain transfer polymerization with ethylene in the presence of alkylaluminium compounds as the corresponding dialkyl complexes do. Investigations of the reactions of the lanthanide aminopyridinato complexes with triethylaluminium or diisobutylaluminium hydride reveal a fast transfer of the aminopyridinato ligand to the aluminium atom. The products of this transfer reaction are aminopyridinato-stabilized dialkylaluminium compounds. One example of these aluminium complexes was characterized by X-ray crystal structure analysis. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]


    Well-defined diblock and triblock copolymers for KrF lithography

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010
    Ting-Yu Lee
    Abstract One of the major components of a photoresist formulation is polymer resin. Well-defined diblock and random copolymer of tert -butyl acrylate (tBA) and 4-acetoxystyrene (StyOAc), as well as triblock and random tertpolymer of tBA, StyOAc, and Sty were prepared by reversible addition fragmentation chain transfer polymerization (RAFT) process. The polymers all possess Mw about ten thousand and PDI less than 1.23. After hydrolysis under basic condition, the hydroxystyrene (StyOH) analogs are obtained and then are formulated as photoresist. Lithographic evaluation under KrF excimer laser shows that random copolymer based photoresist exhibits better S/L patterns according to SEM images. However, the lithographic performance of the terpolymer based resists is similar. 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]


    Preparation of high cis -1,4 polyisoprene with narrow molecular weight distribution via coordinative chain transfer polymerization

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2010
    Changliang Fan
    Abstract High cis -1,4 polyisoprene with narrow molecular weight distribution has been prepared via coordinative chain transfer polymerization (CCTP) using a homogeneous rare earth catalyst composed of neodymium versatate (Nd(vers)3), dimethyldichlorosilane (Me2SiCl2), and diisobutylaluminum hydride (Al(i -Bu)2H) which has strong chain transfer affinity is used as both cocatalyst and chain transfer agent (CTA). Differentiating from the typical chain shuttling polymerization where dual-catalysts/CSA system has been used, one catalyst/CTA system is used in this work, and the growing chain swapping between the identical active sites leads to the formation of high cis -1,4 polyisoprene with narrowly distributed molecular weight. Sequential polymerization proves that irreversible chain termination reactions are negligible. Much smaller molecular weight of polymer obtained than that of stoichiometrically calculated illuminates that, differentiating from the typical living polymerization, several polymer chains can be produced by one neodymium atom. The effectiveness of Al(i -Bu)2H as a CTA is further testified by much broad molecular weight distribution of polymer when triisobutylaluminum (Al(i -Bu)3), a much weaker chain transfer agent, is used as cocatalyst instead of Al(i -Bu)2H. Finally, CCTP polymerization mechanism is validated by continuously decreased Mw/Mn value of polymer when increasing concentration of Al(i -Bu)2H extra added in the Nd(ver)3/Me2SiCl2/Al(i -Bu)3 catalyst system. 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 [source]


    Water-soluble, thermoresponsive, hyperbranched copolymers based on PEG-methacrylates: Synthesis, characterization, and LCST behavior

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2010
    Mario Luzon
    Abstract A series of water-soluble thermoresponsive hyperbranched copoly(oligoethylene glycol)s were synthesized by copolymerization of di(ethylene glycol) methacrylate (DEG-MA) and oligo(ethylene glycol) methacrylate (OEG-MA, Mw = 475 g/mol), with ethylene glycol dimethacrylate (EGD-MA) used as the crosslinker, via reversible addition fragmentation chain transfer polymerization. Polymers were characterized by size exclusion chromatography and nuclear magnetic resonance analyses. According to the monomer composition, that is, the ratio of OEG-MA: DEG-MA: EGD-MA, the lower critical solution temperature (LCST) could be tuned from 25 C to 90 C. The thermoresponsive properties of these hyperbranched copolymers were studied carefully and compared with their linear analogs. It was found that molecular architecture influences thermoresponsive behavior, with a decrease of around 5,10 C in the LCST of the hyperbranched polymers compared with the LCST of linear chains. 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2783,2792, 2010 [source]


    Synthesis of gradient copolymers with complexing groups by RAFT polymerization and their solubility in supercritical CO2

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2009
    Tiphaine Ribaut
    Abstract We report the synthesis of new gradient fluorinated copolymers with complexing groups and soluble in supercritical carbon dioxide (scCO2). Poly(1,1,2,2-tetrahydroperfluorodecyl acrylate- co -acetoacetoxyethyl methacrylate) (poly(FDA- co -AAEM)) and poly(1,1,2,2-tetrahydroperfluorodecyl acrylate- co -vinylbenzylphosphonic acid diethylester) (poly(FDA- co -VBPDE)) gradient copolymers were synthesized by reversible addition fragmentation chain transfer polymerization in ,,,,,-trifluorotoluene. Poly(1,1,2,2-tetrahydroperfluorodecyl acrylate- co -vinylbenzylphosphonic diacid) (poly(FDA- co -VBPDA)) gradient copolymer was efficiently obtained by cleavage of the phosphonic ester groups of poly(FDA- co -VBPDE). The cloud points of these gradient copolymers in dense CO2 were measured in a variable volume view cell at temperatures between 25 and 65 C. The gradient copolymers show very good solubility in compressed CO2 with the decreasing order: poly(FDA- co -AAEM) , poly(FDA- co -VBPDE) > poly(FDA- co -VBPDA). Following a green chemistry strategy, poly(FDA- co -AAEM) gradient copolymer was successfully synthesized in scCO2 with a good control over number-average molecular weight and composition. 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5448,5460, 2009 [source]


    Block copolymers of poly(ethylene oxide) and poly(vinyl alcohol) synthesized by the RAFT methodology

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2009
    Yin-Yin Tong
    Abstract A methodology for the synthesis of well-defined poly(ethylene oxide)- block -poly(vinyl alcohol) (PEO- b -PVA) and PVA- b -PEO- b -PVA polymers was reported. Novel xanthate end-functionalized PEOs were synthesized by a series of end-group transformations. They were then used to mediate the reversible addition,fragmentation chain transfer polymerization of vinyl acetate to obtain well-defined poly(ethylene oxide)- b -poly(vinyl acetate) (PEO- b -PVAc) and PVAc- b -PEO- b -PVAc. When these block copolymers were directly hydrolyzed in methanol solution of sodium hydroxide, polymers with brown color were obtained, which was due to the formation of conjugated unsaturated aldehyde structures. To circumvent these side reactions, the xanthate groups were removed by adding a primary amine before hydrolysis and the products thus obtained were white powders. The polymers were characterized by gel permeation chromatography, 1H NMR spectroscopy and FT-IR. 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1901,1910, 2009 [source]


    Synthesis of azobenzene-containing polymers via RAFT polymerization and investigation on intense fluorescence from aggregates of azobenzene-containing amphiphilic diblock copolymers

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2008
    Jie Xu
    Abstract The well-defined azobenzene-containing homopolymers, poly{6-(4-phenylazophenoxy)hexyl methacrylate (AHMA)} (PAHMA), were synthesized via reversible addition fragmentation chain transfer polymerization (RAFT) in anisole solution using 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN) as the RAFT agent and 2,2,-azobisisobutyronitrile (AIBN) as the initiator. The first-order kinetic plot of the polymerization and the linear dependence of molecular weights of the homopolymers with the relatively low polydispersity index values (PDIs , 1.25) on the monomer conversions were observed. Furthermore, the amphiphilic diblock copolymer, poly{6-(4-phenylazophenoxy)hexyl methacrylate (AHMA)}- b -poly{2-(dimethylamino)ethyl methacrylate (DMAEMA)} (PAHMA- b -PDMAEMA), was prepared with the obtained PAHMA as the macro-RAFT agent. The structures and properties of the polymers were characterized by 1H NMR and GPC, respectively. Interestingly, the amphiphilic diblock copolymers in chloroform (CHCl3) solution (PAHMA23 - b -PDMAEMA97 (4 10,5 M, Mn(GPC) = 18,400 g/mol, PDI = 1.48) and PAHMA28 - b -PDMAEMA117 (6 10,5 M, Mn(GPC) = 19,300 g/mol, PDI = 1.51) exhibited the intense fluorescence emission at ambient temperature. Moreover, the fluorescent intensity of PAHMA- b -PDMAEMA in CHCl3 was sensitive to the ultraviolet irradiation at 365 nm, which increased within the first 10 min and later decreased when irradiation time was prolonged to 30 min or longer. The well distributed, self-assembled micelles composed of azobenzene-containing amphiphilic diblock copolymers, (PAHMA- b -QPDMAEMA)s (QPDMAEMA is quaternized PDMAEMA), in the mixed N,N -dimethyl formamide (DMF)/H2O solutions were prepared. Their fluorescent intensities decreased with the increasing amount of water. 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5652,5662, 2008 [source]


    Functionalization of multiwalled carbon nanotube via surface reversible addition fragmentation chain transfer polymerization and as lubricant additives

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2008
    Xiaowei Pei
    Abstract Polymer-grafted multiwalled carbon nanotube (MWCNT) hybrid composite which possess a hard backbone of MWCNT and a soft shell of brush-like polystyrene (PSt) were synthesized. The reversible addition fragmentation chain transfer (RAFT) agents were successfully immobilized onto the surface of MWCNT first, and PSt chains were subsequently grafted from sidewall of MWCNT via RAFT polymerization. Chemical structure of resulting product and the quantities of grafted polymer were determined by Fourier transform infrared, thermal gravimetric analysis, nuclear magnetic resonance, and X-ray photoelectron spectra. Transmission electron microscopy and field emission scanning electron microscopy images clearly indicate that the nanotubes were coated with a polymer layer. Furthermore, the functionalized MWCNT as additives was added to base lubricant and the tribological property of resultant MWCNT lubricant was investigated with four-ball machines. The results indicate that the functionalization led to an improvement in the dispersion of MWCNT and as additives it amended the tribological property of base lubricant. The mechanism of the significant improvements on the tribological properties of the functionalized MWCNT as additives was discussed. 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3014,3023, 2008 [source]


    Facile preparation of core-crosslinked micelles from azide-containing thermoresponsive double hydrophilic diblock copolymer via click chemistry

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2008
    Xiaoze Jiang
    Abstract Double hydrophilic diblock copolymer, poly(N,N -dimethylacrylamide)- b -poly(N -isopropylacrylamide- co -3-azidopropylacrylamide) (PDMA- b -P(NIPAM- co -AzPAM), containing azide moieties in one of the blocks was synthesized via consecutive reversible addition-fragmentation chain transfer polymerization. The obtained diblock copolymer molecularly dissolves in aqueous solution at room temperature, and can further supramolecularly self-assemble into core-shell nanoparticles consisting of thermoresponsive P(NIPAM- co -AzPAM) cores and water-soluble PDMA coronas above the lower critical solution temperature of P(NIPAM- co -AzPAM) block. As the micelle cores contain reactive azide residues, core crosslinking can be facilely achieved upon addition of difunctional propargyl ether via click chemistry. In an alternate approach in which the PDMA- b -P(NIPAM- co -AzPAM) diblock copolymer was dissolved in a common organic solvent (DMF), the core-crosslinked (CCL) micelles can be fabricated via "click" crosslinking upon addition of propargyl ether and subsequent dialysis against water. CCL micelles prepared by the latter approach typically possess larger sizes and broader size distributions, compared with that obtained by the former one. In both cases, the obtained (CCL) micelles possess thermoresponsive cores, and the swelling/shrinking of which can be finely tuned with temperature, rendering them as excellent candidates as intelligent drug nanocarriers. Because of the high efficiency and quite mild conditions of click reactions, we expect that this strategy can be generalized for the structural fixation of other self-assembled nanostructures. 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 860,871, 2008 [source]


    Thermolyzable polymer networks and star polymers containing a novel, compact, degradable acylal-based dimethacrylate cross-linker: Synthesis, characterization, and thermolysis

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 24 2007
    Efrosyni Themistou
    Abstract A compact, cleavable acylal dimethacrylate cross-linker, 1,1-ethylenediol dimethacrylate (EDDMA), was synthesized from the anhydrous iron(III) chloride-catalyzed reaction between methacrylic anhydride and acetaldehyde. The ability of EDDMA to act as cross-linker was demonstrated by using it for the preparation of one neat cross-linker network, four star polymers of methyl methacrylate (MMA), and four randomly cross-linked MMA polymer networks using group transfer polymerization (GTP). For comparison, the corresponding polymer structures based on the commercially available ethylene glycol dimethacrylate (EGDMA) cross-linker (isomer of EDDMA) were also prepared via GTP. The number of arms of the EDDMA-based star polymers was lower than that of the corresponding EGDMA polymers, whereas the degrees of swelling in tetrahydrofuran of the EDDMA-based MMA networks were higher than those of their EGDMA-based counterparts. Although none of the EDDMA-containing polymers could be cleanly hydrolyzed under basic or acidic conditions, they could be thermolyzed at 200 C within 1 day giving lower molecular weight products. 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5811,5823, 2007 [source]


    Preparation, characterization, and chiral recognition of optically active polymers containing pendent chiral units via reversible addition-fragmentation chain transfer polymerization

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2007
    Jian Wang
    Abstract Optically active polymers bearing chiral units at the side chain were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of 2,2,-azobisisobutyronitrile (AIBN)/benzyl dithiobenzoate (BDB), using a synthesized 6- O - p -vinylbenzyl-1,2:3,4-Di- O -isopropylidene- D -galactopyranose (VBPG) as the monomer. The experimental results suggested that the polymerization of the monomer proceeded in a living fashion, providing chiral group polymers with narrow molecular weight distributions. The optically active nature of the obtained poly (6- O - p -vinylbenzyl-1,2:3,4-Di- O -isopropylidene- D -galactopyranose) (PVBPG) was studied by investigating the dependence of specific rotation on the molecular weight of PVBPG and the concentration of PVBPG in tetrahydrofuran (THF). The results showed the specific rotation of PVBPG increased greatly with the decrease of the concentration of the PVBPG homopolymer. In addition, the effect of block copolymers of PVBPG on the optically active nature was also investigated by preparing a series of diblock copolymers of poly(methyl methacrylate) (PMMA)- b -PVBPG, polystyrene (PS)- b -PVBPG, and poly(methyl acrylate) (PMA)- b -PVBPG. It was found that both the homopolymer and the diblock copolymers possessed specific rotations. Finally, the ability of chiral recognition of the PVBPG homopolymer was investigated via an enantiomer-selective adsorption experiment. 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3788,3797, 2007 [source]


    Original approach to multiblock copolymers via reversible addition,fragmentation chain transfer polymerization

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2007
    Hesna Gemici
    ,,,-Thiol-terminated (co)polymers synthesized via reversible addition,fragmentation chain transfer polymerization can be oxidized to yield multiblock copolymers via the formation of disulfide bridges. [source]


    Latices of poly(fluoroalkyl mathacrylate)- b -poly(butyl methacrylate) copolymers prepared via reversible addition,fragmentation chain transfer polymerization

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2007
    Xiaodong Zhou
    Abstract Poly(fluoroalkyl mathacrylate)- block -poly(butyl methacrylate) diblock copolymer latices were synthesized by a two-step process. In the first step, a homopolymer end-capped with a dithiobenzoyl group [poly(fluoroalkyl mathacrylate) (PFAMA) or poly(butyl methacrylate) (PBMA)] was prepared in bulk via reversible addition,fragmentation chain transfer (RAFT) polymerization with 2-cyanoprop-2-yl dithiobenzoate as a RAFT agent. In the second step, the homopolymer chain-transfer agent (macro-CTA) was dissolved in the second monomer, mixed with a water phase containing a surfactant, and then ultrasonicated to form a miniemulsion. Subsequently, the RAFT-mediated miniemulsion polymerization of the second monomer (butyl methacrylate or fluoroalkyl mathacrylate) was carried out in the presence of the first block macro-CTA. The influence of the polymerization sequence of the two kinds of monomers on the colloidal stability and molecular weight distribution was investigated. Gel permeation chromatography analyses and particle size results indicated that using the PFAMA macro-CTA as the first block was better than using the PBMA RAFT agent with respect to the colloidal stability and the narrow molecular weight distribution of the F-copolymer latices. The F-copolymers were characterized with 1H NMR, 19F NMR, and Fourier transform infrared spectroscopy. Comparing the contact angle of a water droplet on a thin film formed by the fluorinated copolymer with that of PBMA, we found that for the diblock copolymers containing a fluorinated block, the surface energy decreased greatly, and the hydrophobicity increased. 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 471,484, 2007 [source]


    Synthesis and characterization of core,shell-type polymeric micelles from diblock copolymers via reversible addition,fragmentation chain transfer

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2006
    Ping Zhang
    Abstract A method was developed to enable the formation of nanoparticles by reversible addition,fragmentation chain transfer polymerization. The thermoresponsive behavior of polymeric micelles was modified by means of micellar inner cores and an outer shell. Polymeric micelles comprising AB block copolymers of poly(N -isopropylacrylamide) (PIPAAm) and poly(2-hydroxyethylacrylate) (PHEA) or polystyrene (PSt) were prepared. PIPAAm- b -PHEA and PIPAAm- b -PSt block copolymers formed a core,shell micellar structure after the dialysis of the block copolymer solutions in organic solvents against water at 20 C. Upon heating above the lower critical solution temperature (LCST), PIPAAm- b -PHEA micelles exhibited an abrupt increase in polarity and an abrupt decrease in rigidity sensed by pyrene. In contrast, PIPAAm- b -PSt micelles maintained constant values with lower polarity and higher rigidity than those of PIPAAm- b -PHEA micelles over the temperature range of 20,40 C. Structural deformations produced by the change in the outer polymer shell with temperature cycles through the LCST were proposed for the PHEA core, which possessed a lower glass-transition temperature (ca. 20 C) than the LCST of the PIPAAm outer shell (ca. 32.5 C), whereas the PSt core with a much higher glass-transition temperature (ca. 100 C) retained its structure. The nature of the hydrophobic segments composing the micelle inner core offered an important control point for thermoresponsive drug release and the drug activity of the thermoresponsive polymeric micelles. 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3312,3320, 2006 [source]


    Controlled radical polymerization of a trialkylsilyl methacrylate by reversible addition,fragmentation chain transfer polymerization

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2005
    M. N. Nguyen
    Abstract The reversible addition,fragmentation chain transfer (RAFT) polymerization of a hydrolyzable monomer (tert -butyldimethylsilyl methacrylate) with cumyl dithiobenzoate and 2-cyanoprop-2-yl dithiobenzoate as chain-transfer agents was studied in toluene solutions at 70 C. The resulting homopolymers had low polydispersity (polydispersity index < 1.3) up to 96% monomer conversion with molecular weights at high conversions close to the theoretical prediction. The profiles of the number-average molecular weight versus the conversion revealed controlled polymerization features with chain-transfer constants expected between 1.0 and 10. A series of poly(tert -butyldimethylsilyl methacrylate)s were synthesized over the molecular weight range of 1.0 104 to 3.0 104, as determined by size exclusion chromatography. As strong differences of hydrodynamic volumes in tetrahydrofuran between poly(methyl methacrylate), polystyrene standards, and poly(tert -butyldimethylsilyl methacrylate) were observed, true molecular weights were obtained from a light scattering detector equipped in a triple-detector size exclusion chromatograph. The Mark,Houwink,Sakurada parameters for poly(tert -butyldimethylsilyl methacrylate) were assessed to obtain directly true molecular weight values from size exclusion chromatography with universal calibration. In addition, a RAFT agent efficiency above 94% was confirmed at high conversions by both light scattering detection and 1H NMR spectroscopy. 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5680,5689, 2005 [source]


    Living/controlled copolymerization of acrylates with nonactivated alkenes

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 24 2004
    Shengsheng 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 hydrophilic/CO2 -philic poly(ethylene oxide)- b -poly(1,1,2,2-tetrahydroperfluorodecyl acrylate) block copolymers via controlled/living radical polymerizations and their properties in liquid and supercritical CO2

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2004
    Zhi Ma
    Abstract Hydrophilic/CO2 -philic poly(ethylene oxide)- b -poly(1,1,2,2-tetrahydroperfluorodecyl acrylate) block copolymers were synthesized via reversible addition,fragmentation chain transfer (RAFT) polymerization, iodine transfer polymerization (ITP), and atom transfer radical polymerization (ATRP) in the presence of either degenerative transfer agents or a macroinitiator based on poly(ethylene oxide). In this work, both RAFT and ATRP showed higher efficiency than ITP for the preparation of the expected copolymers. More detailed research was carried out on RAFT, and the living character of the polymerization was confirmed by an ultraviolet (UV) analysis of the SC(S)Ph or SC(S)SC12H25 end groups in the polymer chains. The quantitative UV analysis of the copolymers indicated a number-average molecular weight in good agreement with the value determined by 1H NMR analysis. The properties of the macromolecular surfactants were investigated through the determination of the cloud points in neat liquid and supercritical CO2 and through the formation of water-in-CO2 emulsions. 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2405,2415, 2004 [source]


    Solution self-assembly of tailor-made macromolecular building blocks prepared by controlled radical polymerization techniques

    POLYMER INTERNATIONAL, Issue 9 2006
    Jean-Franois 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]


    Kinetics and modeling of charge transfer polymerization of methyl methacrylate

    ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2009
    P. G. Rao
    Abstract The charge transfer polymerization of methyl methacrylate (MMA) in presence of n -butyl amine (nBA) and carbon tetrachloride (CCl4) with dimethyl sulfoxide (DMSO) as solvent was experimentally investigated. The variables include concentrations of MMA, nBA, CCl4, DMSO and reaction temperature. The effect of these variables on monomer conversion, number and weight average molecular weights is discussed. A reaction mechanism is proposed and overall kinetics, propagation, chain transfer and termination constants are evaluated. A mathematical model is proposed for estimating monomer conversion, number and weight average molecular weights. The proposed model is validated using the kinetic constants and compared satisfactorily with experimental data of the present study. Copyright 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]


    Preparation of a Novel Copolymer of Hyperbranched Polyglycerol with Multi-arms of Poly(N -isopropylacrylamide)

    CHINESE JOURNAL OF CHEMISTRY, Issue 4 2010
    Mugang Pan
    Abstract A novel copolymer (PG-PNIPAM) composed of polyglycerol (PG) as core and poly(N -isopropylacrylamide) (PNIPAM) as arms was prepared by the radical addition-fragmentation transfer polymerization (RAFT) of NIPAM in the presence of PG with multi-trithiolcarbonate groups (PG-TTC). The results showed that the RAFT polymerization was controllable and nearly all trithiolcarbonates groups on PG took part in the polymerization. The final PG-PNIPAM copolymer showed a thermally dependent hydrophobic/hydrophilic transition around 28,30C. [source]


    Gold nanoparticle-incorporated core and shell crosslinked micelles fabricated from thermoresponsive block copolymer of N -isopropylacrylamide and a novel primary-amine containing monomer

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2008
    Yueming Zhou
    Abstract A novel primary amine-containing monomer, 1-(3,-aminopropyl)-4-acrylamido-1,2,3-triazole hydrochloride (APAT), was prepared from N -propargylacrylamide and 3-azidopropylamine hydrochloride via copper-catalyzed Huisgen 1,3-dipolar cycloaddition (click reaction). Poly(N -isopropylacrylamide)- b -poly(1-(3,-aminopropyl)-4-acrylamido-1,2,3-triazole hydrochloride), PNIPAM- b- PAPAT, was then synthesized via consecutive reversible addition-fragmentation chain transfer polymerizations of N -isopropylacrylamide and APAT. In aqueous solution, the obtained thermoresponsive double hydrophilic block copolymer dissolves molecularly at room temperature and self-assembles into micelles with PNIPAM cores and PAPAT shells at elevated temperature. Because of the presence of highly reactive primary amine moieties in PAPAT block, two types of covalently stabilized nanoparticles namely core crosslinked and shell crosslinked micelles with ,inverted' core-shell nanostructures were facilely prepared upon the addition of glutaric dialdehyde at 25 and 50 C, respectively. In addition, the obtained structure-fixed micelles were incorporated with gold nanoparticles via in situ reduction of preferentially loaded HAuCl4. High resolution transmission electron microscopy revealed that gold nanoparticles can be selectively loaded into the crosslinked cores or shells, depending on the micelle templates employed. 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6518,6531, 2008 [source]