bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetic investigation of the RAFT polymerization of p‐acetoxystyrene
Authors: Cauët Solène I. , Wooley Karen L. 
Published: May 2010

AbstractThe kinetics of the RAFT polymerization of p‐acetoxystyrene using a trithiocarbonate chain transfer agent, S‐1‐dodecyl‐S′‐(α,α′‐dimethyl‐α″‐acetic acid)trithiocarbonate, DDMAT, was investigated. Parameters including temperature, percentage initiator, concentration, monomer‐to‐chain transfer agent ratio, and solvent were varied and their impact on the rate of polymerization and quality of the final polymer examined. Linear kinetic plots, linear increase of Mn with monomer conversion, and low final molecular weight dispersities were used as criteria for the selection of optimized polymerization conditions, which included a temperature of 70 or 80 °C with 10 mol % AIBN initiator in bulk for low conversions or in 1,4‐dioxane at a monomer‐to‐solvent volume ratio of 1:1 for higher conversions This study opens the way for the use of DDMAT as a chain transfer agent for RAFT polymerization to incorporate p‐acetoxystyrene together with other functional monomers into well‐defined copolymers, block copolymers, and nanostructures. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2517–2524, 2010
Ring‐opening metathesis copolymerization of cyclooctene and a carborane‐containing oxanorbornene
Authors: Simon Yoan C. , Coughlin E. Bryan 
Published: May 2010

AbstractThe incorporation of a silyl‐protected oxanorbornene imide carborane (SONIC) in polyethylene‐like materials is reported. These copolymers were obtained via ring‐opening metathesis copolymerization of (SONIC) and cyclooctene followed by hydrogenation with p‐toluenesulfonylhydrazide. The composition of the copolymer was varied by altering the feed ratio. Structural and thermal properties were investigated and compared with that of a model polymer so as to gauge the impact on the inclusion of the silyl‐functionalized carborane. An initial observation of the modification of the chain sequence upon changing solvent polarity is also discussed. Finally, the potential utilization of these materials as radiation shielding materials is mentioned. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2557–2563, 2010
Conjugated polymers with broad absorption: Synthesis and application in polymer solar cells
Authors: Song Jinsheng , Zhang Chi , Li Cuihong , Li Weiwei , Qin Ruiping , Li Binsong , Liu Zhengping , Bo Zhishan 
Published: May 2010

AbstractA series of main chain donor‐acceptor low‐bandgap conjugated polymers were designed, synthesized, and used for the fabrication of polymer solar cells. The absorption spectra of low‐bandgap conjugated polymers were tuned by the ratio of three copolymerization monomers. The polymers in films exhibited broad absorption ranging from 300 to 1000 nm with optical bandgaps of around 1.40 eV. All of the polymers have been investigated as an electron donor in photovoltaic cells blending with PCBM ([6, 6]‐phenyl C61‐butyric acid methyl ester) as an electron acceptor and power conversion efficiencies (PCEs) of 1.32–1.8% have been obtained. As for P1, PCE increases from 1.67 to 2.44% after adding 1,8‐diiodooctance as an additive. The higher PCEs are probably because of better phase separation of blend films. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2571–2578, 2010
Modeling multiphase latex particle equilibrium morphology
Authors: Reyes Yuri , Asua José M. 
Published: May 2010

AbstractMultiphase waterborne polymer particles provide advantages in more demanding applications and their performance depends on particle morphology. Currently, no general approach to predict the morphology of multiphase latex particles is available. In this work, a model based on Monte Carlo methods was developed for the prediction of equilibrium morphologies of multiphase waterborne systems, such as polymer‐polymer and polymer‐polymer‐inorganic hybrids. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2579–2583, 2010
Highly refractive polymer resin derived from sulfur‐containing aromatic acrylate
Authors: You Nam‐Ho , Higashihara Tomoya , Ando Shinji , Ueda Mitsuru 
Published: May 2010

AbstractNew sulfur‐containing polymers with high‐refractive indices and low birefringences have been developed as UV‐curable high‐refractive polymer resins. The polymers derived from 2,7‐bis[(2‐acryloylethyl)sulfanyl]thianthrene (2,7‐BAST) and 4,4′‐bis[(acryloyloxyethylthio)diphenylsulfide (4,4′‐BADS) were prepared by photopolymerization under UV irradiation. Transparent UV‐cured films were obtained in both cases. Both polymers showed good thermal stability, such as a 5% weight‐loss temperature at 355 °C under nitrogen and glass transition temperatures (Tg) in the range of 94–143 °C. They also showed high‐refractive indices of 1.6531 and 1.6645 at 632.8 nm and low birefringences of 0.0039 and 0.0069 in addition to high transparency in the visible region. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2604–2609, 2010
Free radical and nitroxide mediated polymerization of hydroxy–functional acrylates prepared via lipase–catalyzed transacylation reactions
Authors: Popescu Dragos , Hoogenboom Richard , Keul Helmut , Möller Martin 
Published: May 2010

Abstract3‐Hydroxypropyl acrylate, 4‐hydroxybutyl acrylate, 2‐methyl‐3‐hydroxypropyl acrylate, 2‐hydroxypropyl acrylate, neopentyl glycol acrylate, glyceryl acrylate, and dihydroxyhexyl acrylate were prepared via transacylation reaction of methyl acrylate with diols and triols catalyzed by Candida antarctica lipase B. After removal of the enzyme by filtration and the methyl acrylate by distillation, the monomers were polymerized via free radical polymerization (FRP) with azobisisobutyronitrile as initiator and nitroxide mediated polymerization (NMP) employing Blocbuilder™ alkoxyamine initiator and SG‐1 free nitroxide resulting in hydroxy functional poly(acrylates). The NMP kinetics are discussed in detail. In addition, the polymers obtained by FRP and NMP are compared and the results are related to the amount of bisacrylates that are present in the initial monomer mixtures resulting from the transacylation reactions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2610–2621, 2010
Modifications of the active sites distribution in the Ziegler‐Natta polymerization of propylene using Lewis acids
Authors: Ribour David , Spitz Roger , Monteil Vincent 
Published: May 2010

AbstractHeterogeneous Ziegler‐Natta precatalysts (with phthalate as internal donor) were modified by treatments with various Lewis acids (MCln with M = Ga, Sn, Si, and Sb and n = 3, 4, or 5) before their use in the polymerization of propylene. If performed on previously “detitanated” precatalysts, treatments with SnCl4 and SiCl4 lead to a slight activation but especially to an increase of the tacticity whereas GaCl3 and SbCl5 treatments deactivate the catalyst. The modification method applied to conventional unmodified precatalysts gave similar trends. A significant increase of tacticity (and/or of Tm) and a narrowing of the molecular weight distribution were observed in the case of SnCl4 and SiCl4 treatments. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2631–2635, 2010
Facile one‐pot synthesis of linear and radial block copolymers of styrene and isoprene through a novel coupling agent by living anionic polymerization
Authors: Kumar Santosh , Shah Priyank N. , Kang Beom‐Goo , Min Joon‐Keun , Hwang Woon Sung , Sung Ik Kyung , Shah Shailesh R. , Murthy Chivukula N. , Ahn Seonyoung , Chang Taihyun , Lee Jae‐Suk 
Published: May 2010

AbstractA new methodology is successfully used for the concurrent synthesis of three different copolymers; diblock, triblock, and three‐armed star‐block copolymers of styrene and isoprene via the living anionic polymerization with control over the molecular weight and weight fractions of each block. The room temperature polymerization process has resulted in the well defined linear and radial block copolymers, when the living di‐block of poly(styrene‐b‐isoprene) was coupled using cheap and readily available malonyl chloride as a novel coupling agent giving nearly 100% yield. The resulting block copolymers have narrow polydispersity index (PDI = 1.01–1.09) with a good agreement between the calculated and the observed molecular weights. The results are further supported by fractionation of the block copolymers by reversed‐phase temperature gradient interaction chromatography (RP‐TGIC) technique followed by size exclusion chromatography (SEC). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2636–2641, 2010
Poly(N‐vinylcarbazole) chemically modified graphene oxide
Authors: Zhang Bin , Chen Yu , Zhuang Xiaodong , Liu Gang , Yu Bo , Kang En‐Tang , Zhu Jinhui , Li Yongxi 
Published: May 2010

AbstractA new soluble donor‐acceptor type poly(N‐vinylcarbazole)‐covalently functionalized graphene oxide (GO‐PVK) has been synthesized by reaction of DDAT (S‐1‐dodecyl‐S′‐(α,α′‐dimethyl‐α″‐aceticacid)trithiocarbonate)‐PVK with GO‐toluene‐2,4‐diisocynate. The incorporation of sufficient amount of PVK chains makes the modified GO nanosheets readily dispersible in organic solvents. The resulting material exhibits an enhanced solubility of 10 mg/mL in organic solvents. Covalent grafting of PVK onto the edge and surface of GO nanosheets did not change the carbazole absorption in the ultraviolet region, but substantially reduced the absorption intensity of GO in the visible region. The intensity of the emission band of GO‐PVK at 437 nm was a little bit quenched when compared with that of DDAT‐PVK, suggesting intramolecular quenching from PVK to GO. Such intramolecular quenching process may involve energy or electron transfer between the excited singlet states of the PVK moiety and the GO moiety. The HOMO/LUMO values and the energy bandgap of GO‐PVK experimentally estimated by the onset of the redox potentials are −5.60, −3.58, and 2.02 eV, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2642–2649, 2010
Cationic polymerization of L,L‐lactide
Authors: Baśko Małgorzata , Kubisa Przemysław 
Published: May 2010

AbstractCationic bulk polymerization of L,L‐lactide (LA) initiated by trifluromethanesulfonic acid [triflic acid (TfA)] has been studied. At temperatures 120–160 °C, polymerization proceeded to high conversion (>90% within ∼8 h) giving polymers with Mn ∼ 2 × 104 and relatively high dispersity. Thermogravimetric analysis of resulting polylactide (PLA) indicated that its thermal stability was considerably higher than the thermal stability of linear PLA of comparable molecular weight obtained with ROH/Sn(Oct)2 initiating system. Also hydrolytic stability of cationically prepared PLA was significantly higher than hydrolytic stability of linear PLA. Because thermal or hydrolytic degradation of PLA starting from end‐groups is considerably faster than random chain scission, both thermal and hydrolytic stability depend on molecular weight of the polymer. High thermal and hydrolytic stability, in spite of moderate molecular weight of cationically prepared PLA, indicate that the fraction of end‐groups is considerably lower than in linear PLA of comparable molecular weight. According to proposed mechanism of cationic LA polymerization growing macromolecules are fitted with terminal OH and C(O)OSO2CF3 end‐groups. The presence of those groups allows efficient end‐to‐end cyclization. Cyclic nature of resulting PLA explains its higher thermal and hydrolytic stability as compared with linear PLA. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2650–2658, 2010
Reactivities of carbocations and monomers in carbocationic polymerization and copolymerization
Authors: Sigwalt Pierre , Moreau Michel 
Published: May 2010

AbstractIn carbocationic polymerization and copolymerization, a recent publication concluded that the substituent effect on carbocation reactivity is much larger than its effect on monomer reactivity, and this by a factor 106 in the case of the rate constant k12capp for p‐methylstyrene addition (monomer M2) on, respectively, poly(p‐methoxystyrene)± or poly(p‐methylstyrene)± (M). This conclusion is disputed, as well as the assumption that the rate constants of capping (k12capp) obtained in deactivation reactions of poly(p‐methoxystyrene)± are identical with cross propagation rate constants in copolymerization (k12copol). It is shown that the large calculated k12capp are based on propagation constant values for p‐methylstyrene (k ≈ 109) obtained by the diffusion‐clock method. They are 104 times smaller as found for all styrenes, that is, between 104 and 105 when they are based on the ionic species concentrations. In such a case, the available data are still in agreement with an approximate compensation between the reactivities of a monomer and of the corresponding carbocation. It is also shown that copolymerization data for styrenes are not compatible with k values near to diffusion control, and that variations of log k12capp and log k12copol with the nucleophilicity parameter N of the monomers indicate a much lower selectivity of the monomers in the case of copolymerization. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2666–2680, 2010
Evaluation of peroxide initiators for radical polymerization‐based self‐healing applications
Authors: Wilson Gerald O. , Henderson James W. , Caruso Mary M. , Blaiszik Benjamin J. , McIntire Patrick J. , Sottos Nancy R. , White Scott R. , Moore Jeffrey S. 
Published: May 2010

AbstractThe suitability of various peroxide initiators for a radical polymerization‐based self‐healing system is evaluated. The initiators are compared using previously established criteria in the design of ring opening metathesis polymerization‐based self‐healing systems. Benzoyl peroxide (BPO) emerges as the best performing initiator across the range of evaluation criteria. Epoxy vinyl ester resin samples prepared with microcapsules containing BPO exhibited upwards of 80% healing efficiency in preliminary tests in which a mixture of acrylic monomers and tertiary amine activator was injected into the crack plane of the sample after the initial fracture. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2698–2708, 2010
Synthesis of phenanthroline‐terminated polymers and their Fe(II)‐complexes
Authors: Nagy Miklós , Zsuga Miklós , Rácz Dávid , Kéki Sándor 
Published: May 2010

AbstractWell‐defined mono‐ and bifunctional, phenanthroline‐terminated poly(ethylene glycol) and polyisobutylene capable of polymer network formation were synthesized. The starting materials mono‐ and bi‐phenanthroline‐ (phen) terminated poly(ethylene glycols) (mPEG‐phen, phen‐PEG‐phen) and polyisobutylenes (PIB‐phen, phen‐PIB‐phen) were prepared by the Williamson synthesis and characterized by means of 1H NMR and MALDI‐TOF mass spectrometry. According to UV–Vis spectrophotometry and ESI‐TOF mass spectrometry, the phenanthroline‐terminated polymers underwent quantitative complex formation with ferrous ions in solution. The aqueous solution of mPEG‐phen shows self‐assembly behavior. Important parameters, such as critical micelle concentration and hydrodynamic radius of the aggregates were also determined. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2709–2715, 2010
Immortal SET–LRP mediated by Cu(0) wire
Authors: Jiang Xuan , Rosen Brad M. , Percec Virgil 
Published: May 2010

AbstractCu(0)‐wire/Me6‐TREN is a well established catalyst for living radical polymerization via SET–LRP. Here, it is demonstrated that this polymerization is not just living, but it is in fact the first example of immortal living radical polymerization. The immortality of SET–LRP mediated with Cu(0) wire was demonstrated by attempting, in an unsuccessful way, to irreversible interrupt multiple times the polymerization via exposure to O2 from air. SET–LRP indeed stopped each time when the reaction mixture was exposed to air. However, the SET–LRP reaction, was restarted each time after resealing the reaction vessel and reestablishing the catalytic cycle with the same Cu(0) wire, to produce the same conversion as in the conventional uninterrupted SET–LRP process. Despite the interruption by O2, the reactivated SET–LRP had a good control of molecular weight, molecular weight evolution, and molecular weight distribution, with perfect retention of chain‐end fidelity. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2716–2721, 2010
Nanoporous and proton conductive hydrophobic–hydrophilic copolymer thermoset membranes
Authors: Rahmathullah M. Aflal M. , Snyder Joshua D. , Elabd Yossef A. , Palmese Giuseppe R. 
Published: May 2010

AbstractCopolymers of hydrophobic diglycidyl ether of bisphenol A (DGEBA) vinyl ester (VE) and hydrophilic 2‐acrylamido 2‐methyl 1‐propane sulfonic acid (AMPS) were evaluated as proton conducting membranes for fuel cell applications. Membranes were synthesized using free radical copolymerization in the presence of a common solvent for both monomers, dimethyl formamide (DMF), followed by solvent removal by supercritical CO2 to induce porosity. Micrographs revealed pore sizes below 60 nm with porosity proportional to the initial solvent fraction used. Studies on the states of water showed that the presence of this pore volume significantly altered the freezable water fraction at equivalent AMPS concentrations. Comparison of the moles of water per mole of sulfonic acid (λ) between copolymer membranes and AMPS monomer solutions showed that the nonfreezable water (λ|nonfr) was depressed at high AMPS concentrations, suggesting that differences in interatomic distances between sulfonic acid groups might alter λ|nonfr. The highest average through plane conductivity of membranes was determined to be 30 mS/cm and was comparable to that of Nafion®117 (27 mS/cm). The effective proton mobility, μeff, was calculated and suggested to be a parameter used to capture the effects of membrane structure and swelling while acting as a comparison between different membrane types. Fuel cell tests on membranes at low ion exchange capacities were compared to Nafion®117, with suggestions on improvements of copolymer structures for improved performance. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1245–1255, 2010
Effects of TEMED and EDTA on the structural and mechanical properties of NIPAAm/Na+MMT composite hydrogels
Authors: Yumakgil Kübra , Gökçeören Argun Talat , Erbil Candan 
Published: May 2010

AbstractN‐isopropyl acrylamide (NIPAAm) hydrogels are known as thermosensitive crosslinked polymer networks. In this work, the network parameters of their composites, i.e., NIPAAm/sodium montmorillonite (NIPAAm/Na+MMT) hydrogels synthesized by free radical solution polymerization in the presence of two different types of accelerator (tetramethyl ethylenediamine (TEMED) and ethylenediamine tetraacetic acid (EDTA)) and initiator (potassium persulphate (K2S2O8) and cerium ammonium nitrate ((NH4)2Ce(NO3)6), Ce(IV)) using five different clay content (in the range of 1.0–5.0 wt % of total monomer concentration) at 25 °C were presented and discussed. FTIR spectra, XRD patterns, SEM photographs, and network parameters of the samples indicated that the presence of COOH groups on EDTA molecules was resulted in the formation of exfoliated structures and the activity of EDTA/KPS redox pair was higher than those of TEMED/KPS and EDTA/Ce (IV) pairs. The compression moduli (G) of the hydrogels initiated with EDTA/Ce(IV) redox pair showed smooth and continual changings with increase in Na+MMT content (for swelling equilibrium at 25 °C) on the contrary of EDTA/KPS and TEMED/KPS pairs. It might be related to low initiator efficiency of cerium ammonium nitrate than KPS molecules, having higher effective crosslinking density with increasing clay content. On the other hand, the G moduli of NIPAAm/Na+MMT hydrogels (above their phase transition temperature) initiated with TEMED/KPS redox pair were higher than the others because of the more hydrophobic nature of TEMED molecules. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1256–1264, 2010
Relaxation of fibrils in blends with one viscoelastic component: From bulk to confined conditions
Authors: Cardinaels R. , Moldenaers P. 
Published: May 2010

AbstractUsing a counter rotating parallel plate shear flow cell, shape relaxation of fibrils in a quiescent matrix is studied microscopically. Both the effects of geometrical confinement and component viscoelasticity are systematically explored. By applying a supercritical shear flow for varying amounts of time, droplets with a wide range of initial elongation ratios have been generated. The shape relaxation of these elongated droplets occurs in two stages; the first one consists of shape changes and retraction from a fibril to an ellipsoid, the second one is the retraction of this ellipsoid to a sphere. During both stages of the relaxation process, droplet viscoelasticity has no influence on the relaxation, whereas matrix viscoelasticity and geometrical confinement result in a slower retraction. However, the effect of confinement on the shape relaxation during the first stage of the relaxation process is less pronounced than its influence on the retraction of ellipsoidal droplets. The relaxation time of the second stage of the relaxation corresponds to the relaxation time of initially ellipsoidal droplets. Finally, for confinement ratios up to 0.75 and Deborah numbers around 1, no effect of confinement and component viscoelasticity on the critical initial elongation ratio for breakup during relaxation has been found. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1372–1379, 2010
Viscoelastic properties of decrosslinked irradiation‐crosslinked polyethylenes in supercritical methanol
Authors: Kwon Yong Jin , Hong Soon Man , Koo Chong Min 
Published: May 2010

AbstractThe viscoelastic properties of decrosslinked irradiation‐crosslinked polyethylenes using a supercritical methanol were investigated via oscillatory dynamic shear measurements. Decrosslinked polymers at a low reaction temperature exhibited solid‐like rheological properties, as evidenced by a small slope at G′ and G″, a long relaxation time, slow stress relaxation behavior, and considerable yield stress. In contrast, decrosslinked polymers at a high temperature exhibited liquid‐like rheological properties that included a large slope in G′ and G″, a short relaxation time, fast stress relaxation behavior, and nonyield stress. The difference in the viscoelastic properties of the decrosslinked polyethylenes was attributed to the difference in the gel content with the reaction temperature. A higher gel content induced stronger solid‐like viscoelastic properties. Hence, the rheological measurements were useful for analyzing the molecular structure of decrosslinked polymers using a supercritical fluid. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1265–1270, 2010