bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Convenient Method for the Synthesis of α‐Ethynylphospholes and Modulation of Their π‐Conjugated Systems
Authors: Matano Yoshihiro , Nakashima Makoto , Imahori Hiroshi 
Published: April 2009

AbstractLücken nach Wunsch: α‐Ethinylphosphole, die in situ aus den entsprechenden silylierten Vorstufen erzeugt wurden, lieferten eine Serie von α‐(Arylethinyl)phospholen mit funktionellen Substituenten sowie ein α,α′‐verknüpftes Terphosphol (siehe Schema), das wegen der effizienten π‐Konjugation über drei Phospholringe eine schmale HOMO‐LUMO‐Lücke aufweist.magnified image
The Power of Functional Resins in Organic Synthesis.Herausgegeben von Judit Tulla‐Puche und Fernando Albericio.
Authors: Breinbauer Rolf 
Published: April 2009

AbstractWiley‐VCH, Weinheim 2008. 663 S., geb., 159.00 €.—ISBN 978‐3527319367magnified image
Direct CC Cross‐Coupling of Secondary and Primary Alcohols Catalyzed by a γ‐Alumina‐Supported Silver Subnanocluster
Authors: Shimizu Ken‐ichi , Sato Ryosuke , Satsuma Atsushi 
Published: April 2009

AbstractZum Wohl! Zwei Alkohole (ein primärer und ein sekundärer) werden mithilfe eines Katalysesystems in Form von Silber‐Subnanoclustern auf γ‐Al2O3 durch Wasserstoffautotransfer atomeffizient gekuppelt. Der wiederverwendbare Heterogenkatalysator fördert die Eintopf‐C‐C‐Kreuzkupplung in Gegenwart katalytischer Mengen der schwachen Base Cs2CO3 (siehe Reaktionsmechanismus).magnified image
A Bis(silaselenone) with Two Donor‐Stabilized SiSe Bonds from an Unexpected Stereoconvergent Hydrolysis of a Diselenadisiletane
Authors: Mitra Amitabha , Wojcik Joseph P. , Lecoanet Daniel , Müller Thomas , West Robert 
Published: April 2009

AbstractSiSe matters: Diselenadisiletane 2, formed from direct reaction of a racemic silylene 1 with elemental selenium, gives the first bis(silaselenone) upon hydrolysis with water (3; see picture, C gray, H white, N blue, O red, Se purple, Si green; d(SiSe)=215 pm). The reaction is stereoconvergent: only racemic forms of 3 are obtained from a mixture of racemic and meso forms of 2.magnified image
Platinum(II)‐Catalyzed Intramolecular Cyclization of o‐Substituted Aryl Alkynes through sp3 CH Activation
Authors: Yang Shangdong , Li Zigang , Jian Xing , He Chuan 
Published: April 2009

AbstractRing leader: PtCl2 catalyzes intramolecular cyclization of o‐isopropyl or o‐benzyl aryl alkynes to give substituted indene derivatives with good yields and high selectivity. This reaction appears to proceed through an sp3 CH activation and 1,4‐hydrogen migration pathway (see scheme).magnified image
“On‐Off” Multivalent Recognition: Degradable Dendrons for Temporary High‐Affinity DNA Binding
Authors: Welsh Daniel J. , Jones Simon P. , Smith David K. 
Published: April 2009

AbstractNow you bind it—now you don't! Chemical degradation of a dendritic scaffold allows multivalent interactions with DNA to be “switched off” as the multivalent array of ligands breaks down into smaller fragments, offering an approach by which a molecule can be temporarily endowed with high affinity for a biological target—an important concept in the development of new synthetic systems to intervene in biological pathways.magnified image
Inside Cover: Challenging the Metallocene Dominance in Actinide Chemistry with a Soft PNP Pincer Ligand: New Uranium Structures and Reactivity Patterns (Angew. Chem. Int. Ed. 20/2009)
Authors: Cantat Thibault , Graves Christopher R. , Scott Brian L. , Kiplinger Jaqueline L. 
Published: April 2009

AbstractA standing iceberg illustrates how the soft PNP pincer ligand challenges the metallocene dominance (ship) in actinide chemistry, as described by J. L. Kiplinger and co‐workers in their Communication on page 3681 ff. Replacement of C5Me5 by the PNP ligand is a successful strategy for the promotion of new reactivities and to support new actinide structures. The specific electronic and steric properties of the PNP ligand enable access to structures not available for the C5Me5 ligand set and as yet unreported for uranium. (We thank Mr. Anthony Mancinco for the design of the graphic.)magnified image
Anti‐thrombogenicity of styrene‐butadiene‐styrene triblock copolymer grafted with poly(ethylene glycol)s
Authors: Nagura Masanobu , Nomura Yasutoshi , Gotok Yasuo , Ckkosti Yutaka 
Published: April 2009

AbstractWe transformed hydrophobic/hydrophobic styrene/butadiene/styrene tri‐block copolymer (SBS) to hydrophobic / hydrophilic microphase‐separated surfaces by grafting with hydrophilic poly(ethylene glycol) (PEG) on poly(butadiene) (PB) domain via hydrocarboxylation and hydrobromination and investigated the anti‐thrombogenicity of these surfaces. In the case of SBS cast film from toluene solution, PEG was densely grafted because of the development of an unevenness on the order of several 10 nm on the surface, which had a huge surface area in comparison with poly(butadiene) rubber with its uniformly smooth surface. Grafted PEG (molecular weight = 600) was found to clearly inhibit adhesion and activation of platelets and coagulation of the whole blood component, which is indicative of anti‐thrombogenicity. These properties correspond to a surface coated by a copolymer of 2‐methacryloyl‐oxyethyl phosphorylcholine and n‐butyl methacrylate, which is well known to be the best excellent anti‐thrombogenic material in the world. Melt‐molded SBS film, which also has an uneveness on the order of several 10 nm, showed similar excellent anti‐thrombogenicity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of poly(acrylonitrile–butadiene–styrene)/montmorillonite nanocomposites and degradation studies during extrusion reprocessing
Authors: Karahaliou E.‐K. , Tarantili P. A. 
Published: April 2009

AbstractIn this study, the preparation of organically modified montmorillonite/poly(acrylonitrile–butadiene–styrene) (ABS) nanocomposites was studied by melt blending in a twin‐screw extruder. The composite material was subjected to a series of five extrusion cycles, and the effect of reprocessing on the material's structural properties was investigated. More specifically, chemical changes were studied with attenuated total reflectance/Fourier transform infrared analysis, the thermal response was recorded by differential scanning calorimetry experiments, and the thermal stability was detected with thermogravimetric analysis. Also, the rheological properties of these blends were investigated via melt flow index tests as a measure of their processability during melt mixing and molding processes. Furthermore, the mechanical strength of the obtained mixtures was explored, and the observed interactions were interpreted in terms of the influence of each component on the functional properties of the final mixture. This attempt enriched our knowledge about the recycling of ABS, with the additional aspect of the use of collected data from more complex systems, that is, composite materials, where the montmorillonite nanoparticles play a role in the interactions initiated by repeated processing. The experimental results of this study show that the reprocessing of ABS/montmorillonite induced oxidation products, but the rheological, mechanical, and thermal properties and the thermal and color stabilities of the composites remained almost stable. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanical properties of Bombyx mori silk yarns studied with tensile testing method
Authors: Aksakal Baki , Tsobkallo Ekaterina , Darvish Diana 
Published: April 2009

AbstractThe mechanical properties of Bombyx mori silk yarns and baves were investigated with tensile testing method. After silk yarns were pre‐extended at different strain levels and fixed for a while followed by recovery process, the tensile characteristics were examined in detail. It was commonly observed that low preliminary extensions up to 2–3% do not cause the changes of the mechanical properties and stress‐strain curves because they result in small structural changes and distortions, which were recovered within relatively short time (∼ 1 min) in recovery process. However, pre‐extension values >3% strain lead to great changes of the mechanical properties and fibre structure, i.e., the changes of the shape of stress‐strain curve where additional transition point was observed, increase in the rigidity and stress at rupture, but decrease in extensibility as a result of orientation and destruction of the fibre structure especially in the amorphous region. It was stated that silk fibre consists of two distinct deformation regions, namely first linear region extending up to 2–3% strain and the second region beyond 2–3% strain where the main reorganization processes of the fibre structure, that is, the straining of macromolecular chains especially in the amorphous regions, the orientation of structural units such as β‐sheet microcrystals in stretching direction, and the destruction of macromolecules take place. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Increasing hydration of the epidermis by microcapsules in sterilized products
Authors: Gisbert J. , Ibañez F. , Bonet M. , Monllor P. , Díaz P. , Montava I. 
Published: April 2009

AbstractSome nonserious skin infections can be treated by hydration and antibacterial control. Microcapsules containing aloe‐chitin are often used to treat this kind of problem. Microcapsules were applied to cotton fabrics by padding and sleeves were prepared. A hypoallergenic test was applied to the microcapsule emulsion and hydration of the epidermis was evaluated by capacitance methods. The fabric was sterilized by electron beam treatment to satisfy the antibacterial requisite. The results showed that the aloe is transferred from the fabric to the skin, increasing the level of skin hydration. The electron beam method was also shown to be effective for bacteria and fungi and had no effect on the microcapsule properties. It can, therefore, be confirmed that electron beam sterilization has no harmful effects on the type of microcapsule used in this study. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Investigation on thermo‐rheological properties and stability of SBR modified asphalts containing palygorskite clay
Authors: Zhang Ji , Wang Junlong , Wu Yiqian , Sun Wenxiu , Wang Yunpu 
Published: April 2009

AbstractOne problem of polymer‐modified asphalts (PMAs) is the poor compatibility between polymer and asphalts. In this article, the effects of palygorskite clay (PC) and organomodified palygorskite clay (OPC) on the rheological and morphological properties of styrene butadiene rubber (SBR) modified asphalts are investigated. The dynamic mechanical analysis (DMA) of PC and SBR/PC (OPC) modified asphalts before and after ageing has been characterized by dynamic shear rheometer (DSR). The results indicate that the degree of SBR modification is a function of asphalt‐polymer compatibility. When the polymer concentration is higher, it produces a highly elastic network which increases the viscosity, complex modulus, and elastic response of the mixture, particularly at high service temperatures. However, ageing of the SBR and SBR‐PC mixtures result in a decrease in the elastic response of the modified asphalts. It also have been confirmed that the morphology observed by optical microscopy and scanning electron microscope (SEM) revealed the better compatibility between SBR/PC and asphalt. The storage stability of binder is improved significantly. Compared with PC, OPC shows better effect in improving viscoelastic properties and rutting resistance of the mixture, which contributes to the better improvement of interfacial adhesion based on larger size between layers in OPC‐modified asphalts. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and properties of poly(urethane‐imide) diacid/epoxy composites cured with an aziridine system
Authors: Liu Pinggui , Zhang Qingfang , He Lihua , Xie Qingji , Ding Heyan 
Published: April 2009

AbstractA poly(urethane‐imide) diacid (PUI), a diimide‐diacid with a soft structure unit, was directly synthesized from the reaction of trimellitic anhydride and isocyanate terminated polyurethane prepolymer. FT‐IR and NMR were used to characterize its chemical structure. Then PUI was blended with two types of epoxy resins with different chemical structures, diglycidyl ether of bisphenol A (DGEBA) and novolac epoxy (EPN). After curing the blends with polyfunctional aziridine CX‐100, novel polyurethane/epoxy composites were obtained as transparent yellowish films. Thermal, chemical, and morphological properties of the cured composites were investigated using thermal analysis, SEM, TEM, chemical resistance, respectively. All experimental data indicated that epoxy modified PUI composites possessed higher thermal stability than that unmodified PUI, and that modified PUI had much better chemical resistance. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Novel self‐supported natural and synthetic polymer membranes for air humidification
Authors: Bhat S.D. , Manokaran A. , Sahu A.K. , Pitchumani S. , Sridhar P. , Shukla A.K. 
Published: April 2009

AbstractNovel self‐supported natural and synthetic polymer membranes of chitosan‐hydroxy ethyl cellulose‐montmorillonite (CS‐HEC‐MMT) and polyvinyl alcohol (PVA)‐polystyrene sulfonic acid (PSSA) are prepared by solution casting method followed by crosslinking. These membranes are employed for air humidification at varying temperatures between 30°C and 70°C and their performances are compared with commercial Nafion® membranes. High water fluxes with desired humidified‐air output have been achieved for CS‐HEC‐MMT and PVA‐PSSA hybrid membranes at air‐flow rates of 1–10 slpm. Variation in the air/water mixing ratio, dew point, and relative humidity that ultimately results in desired water flux with respect to air‐flow rates are also quantified for all the membranes. Water flux values for CS‐HEC‐MMT are less than those for Nafion® and PVA‐PSSA membranes, but the operational stability of CS‐HEC‐MMT membrane is higher than PVA‐PSSA and comparable with Nafion® both of which can operate up to 70°C at repetitive cycles of humidification. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of acrylic core–shell rubber particles on the particulate flow and toughening of PVC
Authors: Moghbeli M. R. , Tolue Sh. 
Published: April 2009

AbstractDifferent types of acrylic core–shell rubber particles with a poly(butyl acrylate) (PBA) core and a grafted poly(methyl methacrylate) (PMMA) shell were synthesized. The average size of acrylic core–shell latex particles ranged from 100 to 170 nm in diameter, having the core gel content in the range of 35–80%. The melt blending behavior of the poly(vinyl chloride) (PVC) and the acrylic core–shell rubber materials having different average particle sizes and gel contents was investigated in a batch mixing process. Although the torque curves showed that the particulate flow of the PVC in the blends was dominant, some differences were observed when the size and gel content of the particles varied. This behavior can be attributed to differences in the plasticizing effect and dispersion state of various types of core–shell rubber particles, which can vary the gelatin process of the PVC in the mixing tool. On the other hand, the highest toughening efficiency was obtained using core–shell rubber particles with the smallest particle size (i.e., 100 nm). The results showed that increasing the gel content of the core–shell impact modifiers with the same particle size improved the particle dispersion state in the PVC matrix. The toughening efficiency decreased for the blends containing 100 and 170 nm rubber particles as the gel content increased. Nevertheless, unexpected behavior was observed for the blends containing 140 nm rubber particles. It was found that a high level of toughness could be achieved if the acrylic core–shell rubber particles as small as 100 nm had a lower gel content. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Dynamic mechanical and morphological behavior of blends of polystyrene and poly[acrylonitrile‐g‐(ethylene‐co‐propylene‐co‐diene)‐g‐styrene] prepared by in situ polymerization of styrene
Authors: Lourenço Emerson , Gonçalves Maria do Carmo , Felisberti Maria Isabel 
Published: April 2009

AbstractPS/AES blends were prepared by in situ polymerization of styrene in the presence of AES elastomer, a grafting copolymer of poly(styrene‐co‐acrylonitrile) – SAN and poly(ethylene‐co‐propylene‐co‐diene)–EPDM chains. These blends are immiscible and present complex phase behavior. Selective extraction of the blends' components showed that some fraction of the material is crosslinked and a grafting of PS onto AES is possible. The morphology of the noninjected blends consists of spherical PS domains covered by a thin layer of AES. After injection molding, the blends show morphology of disperse elastomeric phase morphology in a rigid matrix. Two factors could contribute to the change of morphology: (1) the stationary polymerization conditions did not allow the mixture to reach the equilibrium morphology; (2) the grafting degree between PS and AES was not high enough to ensure the morphological stability against changes during processing in the melting state. The drastic change of EPDM morphology from continuous to disperse phase has as consequence a decrease in the intensity of the loss modulus peaks corresponding to the EPDM glass transition. However, the storage modulus at temperatures between the glass transition of EPDM and PS/SAN phases does not change significantly. This effect was attributed to the presence of the SAN rigid chains in the AES. © 2009 Wiley Periodicals, Inc. Journal of Applied Polymer Science, 2009
Effect of polymer additives and process temperature on the physical properties of bitumen‐based composites
Authors: Doğan Mehmet , Bayramli Erdal 
Published: April 2009

AbstractPolymer modified bitumen (PMB) is a binder obtained by the incorporation of polymer into the bitumen by mechanical mixing or chemical reaction. This study deals with the modification of bitumen with three types of polymers (LDPE, EVA, and SBS) in the presence of filler (CaCO3). The morphological, mechanical, rheological properties, and thermal conductivity of the PMBs have been analyzed by scanning electron microscopy, tensile testing, melt flow index (MFI) measurements and hot wire method, respectively. The results indicate that the above‐mentioned properties of PMBs are influenced by polymer and bitumen nature and its composition. The mechanical properties of composites prepared at different temperatures exhibit small differences. In general, the inclusion of polymer increases tensile strength and Young's modulus and reduces percentage strain and MFI values, also, polymer inclusion reduces the thermal conductivity values of the composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Sulfonated poly(ether sulfone)‐based catalyst binder for a proton‐exchange membrane fuel cell
Authors: Krishnan N. Nambi , Kim Hyoung‐Juhn , Jang Jong Hyun , Lee Sang‐Yeop , Cho EunAe , Oh In‐Hwan , Hong Seong‐Ahn , Lim Tae‐Hoon 
Published: April 2009

AbstractSulfonated poly(ether sulfone) copolymer (PES 60) and its partially fluorinated analogue (F‐PES 60) were synthesized via the nucleophilic aromatic polycondensation of commercially available monomers to make a polymer electrolyte membrane and a binding material in the electrodes of a membrane–electrode assembly (MEA). PES 60 and F‐PES 60 showed proton conductivities of 0.091 and 0.094 S/cm, respectively, in water at room temperature. The copolymer was dissolved in the mixture of alcohol and water to get a 1 wt % binder solution. A catalyst slurry was prepared with the copolymer solution and sprayed on the copolymer (PES 60 or F‐PES 60) membrane to obtain a MEA. Both PES 60 and F‐PES 60 based MEAs were fabricated with different amounts of their binder in the electrodes to examine the effect of the copolymer binder in the catalyst layer on the fuel cell performance. The MEA with 2 wt % copolymer binder in the electrodes showed the best fuel cell performance. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Transglutaminase‐mediated crosslinking of gelatin onto wool surfaces to improve the fabric properties
Authors: Cui Li , Wang Qiang , Wang Ping , Huan Qingsong , Fan Xuerong 
Published: April 2009

AbstractIn this study, transglutaminase (TGase)‐mediated crosslinking of gelatin on the surface of wool and its effect on the properties of wool fabric were investigated. For the wool fabric used in this study, gelatin (3 g/L) treatment for 1 h combined with 20 U/g of fabric microbial TGase reduced the area shrinkage of KMnO4‐pretreated wool fabric from 6.53 ± 0.06 to 1.92 ± 0.15%, which was more effective than that treated with gelatin alone (in which the area shrinkage was reduced to 4.02 ± 0.10%). At the same time, the tensile strength recovered from 267 ± 2.0 to 335 ± 2.1 N. The antifelting ability of treated wool fabric exhibited better washing durability. Scanning electron micrographs showed that the gelatin material smoothed the wool fiber surface by coating or filling the raised scales of the wool with TGase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Physicochemical characterization of a pectin/calcium matrix containing a large fraction of calcium chloride: Implications for sigmoidal release characteristics
Authors: Wei Xiuli , Chen Zhukang , Lu Yi , Xu Huinan , Chen Guiliang , Wu Wei 
Published: April 2009

AbstractThe physicochemical properties of pectin/calcium matrix tablets were studied with an emphasis on the effect of over 50% of calcium chloride to better understand the fundamentals of the drug‐release mechanisms. The absence of the adsorption of methylene blue onto the calcium‐containing pectin matrix served as evidence of the calcium‐ion‐induced in situ crosslinking of pectin chains. Visual and scanning electron microscopy observation showed the reinforced robustness of the pectin/calcium matrix, whereas cryo‐SEM revealed the formation of a pectin aggregate network as a result of calcium‐induced crosslinking. The aggregate network underwent gradual erosion to a lower density, which indicated the erosion of the matrix. However, little change in the texture of the pectin/calcium matrix was observed at earlier times, which was interpreted as the initial stages of drug‐release retardation. The apparent viscosity of the pectin aqueous dispersion increased biphasically as the calcium amount increased. The initial sharp increase was interpreted as calcium‐induced crosslinking, whereas the following gradual increase was ascribed to a possible salt effect. We concluded that the salt effect and calcium‐induced crosslinking contributed to a series of physical changes of the pectin matrix, which correlated to the sigmoidal release of indomethacin from the pectin/calcium matrix tablet. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009