bluuebunny/crossref_metadata_2025 huggingface dataset:
Perfect Bi4Ti3O12 Single‐Crystal Films via Flux‐Mediated Epitaxy
Authors: Takahashi R. , Yonezawa Y. , Ohtani M. , Kawasaki M. , Nakajima K. , Chikyow T. , Koinuma H. , Matsumoto Y.
Published: January 2006

Excellent crystallinity of material films and atomic control of their surface/interface, sufficient for the realization of their optimal physical properties, are technological premises for modern functional‐device applications. Bi4Ti3O12 and related compounds attract much interest as highly insulating, ferroelectric materials for use in ferroelectric random‐access memories. However, it has been difficult thus far for Bi4Ti3O12 films to satisfy such requirements when formed using vapor‐phase epitaxy, owing to the high volatility of Bi in a vacuum. Here, we demonstrate that flux‐mediated epitaxy is one of the most promising and widely applicable concepts to overcome this inevitable problem. The key point of this process is the appropriate selection of a multi‐component flux system. A combinatorial approach has led to the successful discovery of the novel flux composition of Bi–Cu–O for Bi4Ti3O12 single‐crystal film growth. The perfect single‐crystal nature of the stoichiometric Bi4Ti3O12 film formed has been verified through its giant grain size and electric properties, equivalent to those of bulk single crystals. This demonstration has broad implications, opening up the possibility of preparing stoichiometric single‐crystal oxide films via vapor‐phase epitaxy, even if volatile constituents are required.
Highly Efficient Green‐Emitting Phosphorescent Iridium Dendrimers Based on Carbazole Dendrons
Authors: Ding J. , Gao J. , Cheng Y. , Xie Z. , Wang L. , Ma D. , Jing X. , Wang F.
Published: January 2006

Green‐emitting iridium dendrimers with rigid hole‐transporting carbazole dendrons are designed, synthesized, and investigated. With second‐generation dendrons, the photoluminescence quantum yield of the dendrimers is up to 87 % in solution and 45 % in a film. High‐quality films of the dendrimers are fabricated by spin‐coating, producing highly efficient, non‐doped electrophosphorescent organic light‐emitting diodes (OLEDs). With a device structure of indium tin oxide/poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonic acid)/neat dendrimer/1,3,5‐tris(2‐N‐phenylbenzimidazolyl)benzene/LiF/Al, a maximum external quantum efficiency (EQE) of 10.3 % and a maximum luminous efficiency of 34.7 cd A–1 are realized. By doping the dendrimers into a carbazole‐based host, the maximum EQE can be further increased to 16.6 %. The integration of rigid hole‐transporting dendrons and phosphorescent complexes provides a new route to design highly efficient solution‐processable dendrimers for OLED applications.
Stable, Superhydrophobic, and Conductive Polyaniline/Polystyrene Films for Corrosive Environments
Authors: Zhu Y. , Zhang J. , Zheng Y. , Huang Z. , Feng L. , Jiang L.
Published: January 2006

A polyaniline/polystyrene composite film with a lotus‐leaf‐like structure is prepared via a simple electrospinning method. The film shows stable superhydrophobicity and conductivity, even in many corrosive solutions, such as acidic or basic solutions over a wide pH range, and also in oxidizing solutions. The special surface composition and morphology are the two important aspects that induce such unusual properties. The polystyrene content can strongly influence the morphology of the composite films, which thus display different superhydrophobicities and conductivities.
Industrial‐Scale Palladium‐Catalyzed Coupling of Aryl Halides and Amines –A Personal Account
Authors: Buchwald Stephen L. , Mauger Christelle , Mignani Gerard , Scholz Ulrich
Published: January 2006

The palladium‐catalyzed coupling of amines and aryl halides or aryl alcohol derivatives has matured from an exotic small‐scale transformation into a very general, efficient and robust reaction during the last ten years. This article reports several applications of this method from an industrial vantage point, including ligand synthesis, synthesis of arylpiperazines, arylhydrazines and diarylamines. Much emphasis in placed on issues of scale‐up and safety to underline the potential of CN couplings as solutions for industrial‐scale synthetic problems.
A Selective Transformation of Flavanones to 3‐Bromoflavones and Flavones Under Microwave Irradiation
Authors: Zhou Zhongzhen , Zhao Peiliang , Huang Wei , Yang Guangfu
Published: January 2006

This paper presents the first report of a highly selective transformation of flavanones to 3‐bromoflavones or flavones by microwave irradiation of the corresponding flavanone reactants and N‐bromosuccinimide (NBS) in the presence of a catalytic amount of 2,2′‐azobis(isobutyronitrile) (AIBN). The combination of good to excellent yields, shorter reaction time (10 min), and high levels of functional group compatibility make this an attractive synthetic approach to 3‐bromoflavones and flavones.
Ru‐(Phosphine‐Oxazoline) Complexes as Effective, Industrially Viable Catalysts for the Enantioselective Hydrogenation of Aryl Ketones
Authors: Naud Frédéric , Malan Christophe , Spindler Felix , Rüggeberg Carsten , Schmidt Andreas T. , Blaser Hans‐Ulrich
Published: January 2006

Complexes prepared in situ from RuCl2(PPh3)3 and chiral phosphine‐oxazoline ligands are effective catalysts for the hydrogenation of various aryl ketones with ees up to 99% and substrate to catalyst ratios of 10,000–50,000; the reaction tolerates high substrate concentrations and a pilot process has been developed for the hydrogenation of 3,5‐bistrifluoromethyl acetophenone.
Catalytic Isomerization of Allylic Alcohols by (η6‐p‐Cymene)‐ Ruthenium(II) Complexes in Organic and Aqueous Media: New Recyclable and Highly Efficient Catalysts in Water Containing Ammonium‐Functionalized Ligands
Authors: Crochet Pascale , Díez Josefina , Fernández‐Zúmel Mariano A. , Gimeno José
Published: January 2006

The water‐soluble complexes [RuCl2(η6‐p‐cymene){κ‐(P)‐PPh3n(OCH2CH2NMe3)n}][SbF6]n [n=1 (4a), 2 (4b) or 3 (4c)] have been prepared from the neutral precursors [RuCl2(η6‐p‐cymene){κ‐(P)‐PPh3‐n(OCH2CH2NMe2)n}] [n=1 (2a), 2 (2b) or 3 (2c)] and MeI via quaternization of the nitrogen atom of the terminal aminoalkyl groups, and subsequent counteranion exchange by the treatment with AgSbF6. Complexes 2a–c and 4a–c have proven to be highly active catalysts for isomerization of allylic alcohols in THF and aqueous media, respectively. Moreover, the water‐soluble catalysts 4a–c can be reused after a simple extraction process at the end of the reaction. In particular, 4c presents a remarkable capability to be recycled, being active during 10 successive runs.
Isomerization of Propargylic Alcohols into α,β‐Unsaturated Carbonyl Compounds Catalyzed by the Sixteen‐Electron Allyl‐Ruthenium(II) Complex [Ru(η3‐2‐C3H4Me)(CO)(dppf)][SbF6]
Authors: Cadierno Victorio , García‐Garrido Sergio E. , Gimeno José
Published: January 2006

The 16‐e− (η3‐allyl)‐ruthenium(II) complex [Ru(η3‐2‐C3H4Me)(CO)(dppf)][SbF6] is an efficient catalyst for the regioselective isomerization of terminal propargylic alcohols HCCCR1R2(OH) into α,β‐unsaturated aldehydes R1R2CCHCHO or ketones R3R4CC(R1)COMe (if R2=CHR3R4) under mild conditions. This complex has been also used as catalyst for the preparation of conjugated 1,3‐enynes via dehydration of propargylic alcohols.
A Simple and Efficient Copper‐Free Catalytic System Based on a Palladacycle for the Arylation of Alkynes
Authors: Consorti Crestina S. , Flores Fabricio R. , Rominger Frank , Dupont Jairton
Published: January 2006

The palladacycle [Pd(k2‐C,N‐C(C6H5)C(Cl)CH2NMe2)(μ‐Cl)]2 (1) derived from the chloropalladation of 3‐(dimethylamino)‐1‐phenyl‐1‐propyne and its phosphine adduct [Pd(k2‐C,N‐C(C6H5)C(Cl)CH2NMe2)P(4‐CF3C6H4)3(Cl)] (3) promote the alkynylation of bromo‐ and iodoarenes under relatively mild reaction conditions. The coupling of iodoarenes and activated bromoarenes with terminal alkynes can be conducted at room temperature. Turnover numbers have been achieved up to 105 with iodoarenes and up to 94 for deactivated bromoarenes but at higher temperatures (120 °C). Selective poisoning experiments (Hg, Collman and Crabtree tests) suggest that soluble Pd(0) species are the most probable catalytically active species involved in this Csp2–Csp coupling reaction.
A Clean, Facile and Practical Synthesis of α‐Oxoketene S,S‐Acetals in Water
Authors: Ouyang Yan , Dong Dewen , Yu Haifeng , Liang Yongjiu , Liu Qun
Published: January 2006

A clean, facile and practical synthesis of α‐oxoketene S,S‐acetals in water has been developed. Catalyzed by tetrabutylammonium bromide (TBAB) at room temperature in water, a range of β‐dicarbonyl compounds have been converted to the corresponding α‐oxoketene S,S‐acetals in very high yields. The catalyst in the aqueous phase can be recycled after the separation of organic products.
Conjugate Addition of Indoles to Nitroalkenes Promoted by Basic Alumina in Solventless Conditions
Authors: Ballini Roberto , Clemente Roberto Rabanedo , Palmieri Alessandro , Petrini Marino
Published: January 2006

Basic alumina is found to promote the conjugate addition of indoles to nitroalkenes in solventless conditions at 60 °C. Nitroalkenes can be replaced by nitro alcohols that are converted into nitroolefins under the reaction conditions. Alternatively, a tandem nitroaldol‐dehydration allows the utilization of nitroalkanes and aldehydes as remote precursors of reactive nitroalkenes in a ‘one–pot’ synthesis of 3‐substituted indoles.
Curing of epoxy systems at sub‐glass transition temperature
Authors: Kroutilová Irena , Matějka Libor , Sikora Antonín , Souček Kamil , Staš Lubomír
Published: January 2006

Three epoxy‐amine thermoset systems were cured at a low ambient temperature. Evolution of the reaction kinetics and molecular structure during cure at the sub‐glass transition temperature was followed by DSC and chemorheology experiments. The effect of vitrification and the reaction exotherm on curing and final mechanical properties of the epoxy thermosets was determined. Thermomechanical properties of the low‐temperature cured systems depend on the reaction kinetics and volume of the reaction mixture. Curing of the fast‐reacting system in a large volume (12‐mm thick layer) resulted in the material with Tg exceeding the cure temperature by 70–80°C because of an exothermal temperature rise. However, the reaction in a too large volume (50‐mm layer) led to thermal degradation of the network. In contrast, thin layers (1.5 mm) were severely undercured. Well‐cured epoxy thermosets could be prepared at sub‐Tg temperatures by optimizing reaction conditions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3669–3676, 2006
Kinetic study on the UV‐induced photopolymerization of epoxy acrylate/TiO2 nanocomposites by FTIR spectroscopy
Authors: Li Fusheng , Zhou Shuxue , You Bo , Wu Limin
Published: January 2006

The kinetics of the photopolymerization of epoxy acrylate/TiO2 nanocomposites, with 2′2‐dimethoxy‐1,2‐diphenylethan‐1‐one (Irgacure 651) or benzophenone/N‐methyl diethanolamine as photoinitiators, were studied by FTIR spectroscopy. It was found that nanocomposites had a decreasing photopolymerization rates in comparison with pure epoxy acrylate. The photopolymerization rate of the nanocomposite could also be influenced by initiator types, oxygen, film thickness, irradiation intensity, dispersing media of TiO2 slurry, and so forth. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3281–3287, 2006
Morphology, thermal, and mechanical properties of flame‐retardant silicone rubber/montmorillonite nanocomposites
Authors: Yang Ling , Hu Yuan , Lu Hongdian , Song Lei
Published: January 2006

Flame‐retardant methyl vinyl silicone rubber (MVMQ)/montmorillonite nanocomposites were prepared by solution intercalation method, using magnesium hydroxide (MH) and red phosphorus (RP) as synergistic flame‐retardant additives, and aero silica (SiO2) as synergistic reinforcement filler. The morphologies of the flame‐retardant MVMQ/montmorillonite nanocomposites were characterized by environmental scanning electron microscopy (ESEM), and the interlayer spacings were determined by small‐angle X‐ray scattering (SAXS). In addition to mechanical measurements and limited oxygen index (LOI) test, thermal properties were tested by thermogravimetric analysis (TGA). The decomposition temperature of the nanocomposite that contained 1 wt % montmorillonite can be higher (129°C) than that of MVMQ as basal polymer matrix when 5% weight loss was selected as measuring point. This kind of silicone rubber nanocomposite is a promising flame‐retardant polymeric material. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3275–3280, 2006
Radiation‐processed styrene–butadiene‐co‐ethylene– propylene diene rubber blends: Compatibility and swelling studies
Authors: Dubey K. A. , Bhardwaj Y. K. , Chaudhari C. V. , Sabharwal S.
Published: January 2006

Radiation‐induced compatibility behavior of SBR–EPDM blends of different composition has been investigated using dilute solution viscometry. The results show that at a threshold dose of 10 kGy, good interaction between the components of the blends is achieved. Higher radiation doses lead to formation of crosslinked three‐dimensional copolymer network, whose swelling depends on the radiation dose imparted. The anomalous diffusion of solvent into the gels was confirmed by rigorous treatment of the swelling data. Permeation data agreement with the series model indicated that in SBR–EPDM blends EPDM exists as continuous phase and SBR as dispersed phase. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3638–3649, 2006
Nonisothermal crystallization kinetics of poly(butylene terephthalate)/montmorillonite nanocomposites
Authors: Wu Defeng , Zhou Chixing , Fan Xie , Mao Dalian , Bian Zhang
Published: January 2006

The melt intercalation method was employed to prepare poly(butylene terephthalate) (PBT)/montmorillonite (MMT) nanocomposites, and the microstructures were characterized with X‐ray diffraction and transmission electron microscopy. Then, the nonisothermal crystallization behavior of the nanocomposites was studied with differential scanning calorimetry (DSC). The DSC results showed that the exothermic peaks for the nanocomposites distinctly shifted to lower temperatures at various cooling rates in comparison with that for pure PBT, and with increasing MMT content, the peak crystallization temperature of the PBT/MMT hybrids declined gradually. The nonisothermal crystallization kinetics were analyzed by the Avrami, Jeziorny, Ozawa, and Mo methods on the basis of the DSC data. The results revealed that very small amounts of clay (1 wt %) could accelerate the crystallization process, whereas higher clay loadings reduced the rate of crystallization. In addition, the activation energy for the transport of the macromolecular segments to the growing surface was determined by the Kissinger method. The results clearly indicated that the hybrids with small amounts of clay presented lower activation energy than PBT, whereas those with higher clay loadings showed higher activation energy. The MMT content and the crystallization conditions as well as the nature of the matrix itself affected the crystallization behavior of the hybrids. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3257–3265, 2006
Preparation, modification, and characterization of acrylic cements
Authors: Basgorenay Burcu , Ulubayram Kezban , Serbetci Kemal , Onurhan Erdal , Hasirci Nesrin
Published: January 2006

Acrylic cements with different compositions were prepared by mixing the solid part (composed of poly(methyl methacrylate), PMMA, and benzoyl peroxide, BPO) and the liquid part (composed of methyl methacrylate, MMA, and N,N‐dimethyl‐p‐toluidine, DMPT), modified by addition of hydroxyapatite (HA) and ammonium nitrate (AN) and characterized by measuring thermal and mechanical properties. Three sets of samples were prepared. For B‐group, the total amount of solid including HA was constant but the PMMA to HA ratio was varied. For C‐group, polymer/monomer ratio was constant and varying amounts of HA was added. For D‐group, polymer/monomer ratio was kept constant and AN was added in varying amounts. Effects of these composition changes on the properties of the cement such as setting time, curing temperature, tensile and compression strength, and deformation were examined. For B‐group samples, no linear change was observed in thermal (curing temperatures were all quite high) and mechanical (between 27 and 19 MPa for tensile, and 98 and 116 MPa for compression strength) properties upon change of HA content with change in solid/liquid ratio. For C and D‐group samples, a continuous decrease in curing temperature from 114 to 101°C and from 94 to 73°C was observed upon increasing HA and AN contents, respectively. Also, a linear relation was observed in compression strength (from 98 to 111 MPa) and in tensile strength (from 27 to 21 MPa) upon HA addition, and in the compression strength (from 103 to 85 MPa) and in the tensile strength (from 22 to 17 MPa) with NA addition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3631–3637, 2006
Comparison of the curing kinetics of the RTM6 epoxy resin system using differential scanning calorimetry and a microwave‐heated calorimeter
Authors: Navabpour Parnia , Nesbitt Alan , Degamber B. , Fernando G. , Mann Tim , Day Richard
Published: January 2006

The cure of a commercial epoxy resin system, RTM6, was investigated using a conventional differential scanning calorimeter and a microwave‐heated calorimeter. Two curing methods, dynamic and isothermal, were carried out and the degree of cure and the reaction rates were compared. Several kinetics models ranging from a simple nth order model to more complicated models comprising nth order and autocatalytic kinetics models were used to describe the curing processes. The results showed that the resin cured isothermally showed similar cure times and final degree of cure using both conventional and microwave heating methods, suggesting similar curing mechanisms using both heating methods. The dynamic curing data were, however, different using two heating methods, possibly suggesting different curing mechanisms. Near‐infrared spectroscopy showed that in the dynamic curing of RTM6 using microwave heating, the epoxy‐amine reaction proceeded more rapidly than did the epoxy‐hydroxyl reaction. This was not the case during conventional curing of this resin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3658–3668, 2006
Synthesis and characterization of acrylamide and 2‐hydroxylpropyl methacrylate hydrogels for specialty applications
Authors: Chauhan Ghanshyam S. , Chauhan Sandeep , Chauhan Kalpana , Sen Usha
Published: January 2006

To modify acrylamide (AAm) hydrogels for specialty applications, it was copolymerized with 2‐Hydroxypropyl methacrylate (HPMA) in different molar ratio at 25°C in 1:1 water–acetone solvent system, using ammonium persulphate (APS) and N,N,N,N‐tetramethyl ethylene diamine (TEMED) initiator–accelerator system. Two series of hydrogels were thus prepared using two different crosslinkers—ethylene glycol dimethacrylate (EGDMA) and N,N‐methylene bisacrylamide (N,N‐MBAAm). To affect property profile of the hydrogels, concentration of HPMA was varied over a range of five concentrations from 3.5 to 28 mM. Hydrogels were further functionalized by partial hydrolysis with NaOH and Hofmann amide degradation reaction. FTIR, Nitrogen analysis, and SEM were used to establish monomer reactivity and structure relationship of the hydrogels. Metal ion uptake was studied as a function of various structural aspects of the hydrogels. Water uptake behavior of the hydrogels was studied at constant time, temperature, and pH, both pre and post metal loading. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3040–3049, 2006
The shear strength of Calabrian pine (Pinus brutia Ten.) bonded with polyurethane and polyvinyl acetate adhesives
Authors: Burdurlu Erol , Kılıç Yılmaz , Eli̇bol G. Cankız , Kılıç Murat
Published: January 2006

In this study, the change in shear strength on radial and tangential surfaces of Calabrian Pine (Pinus brutia Ten.) wood having different roughness values as the result of sawing with a circular ripsaw, planing and sanding, and bonded with polyurethane (PU) and polyvinyl acetate (PVAc) adhesives at the pressure levels of 3, 6, and 9 kgf/cm2, was studied. Each of the 360 specimens prepared to determine the effect of the variables on bond performance were subjected to shear test in an universal test machine in accordance with the ASTM D 905–98 standards. The values obtained were analyzed statistically and the results were interpreted. The highest shear strength (11.83 N/mm2) for plane of cut was obtained on the tangential surface after sanding and applying PVAc adhesive with a pressing pressure of 9 kgf/cm2. The lowest shear strength (6.01 N/mm2) was obtained in the joinings made on the planed surfaces by using PU adhesive and a pressing pressure of 3 kgf/cm2. The highest shear strength (9.10 N/mm2) on the radial surface was obtained after sanding and applying PVAc adhesive and pressing with a pressure of 6 kgf/cm2. The lowest shear strength (3.76 N/mm2) was obtained in the specimens whose surfaces were sanded and glued with PU adhesive with a pressing pressure of 3 kgf/cm2. In general, in the radial surfaces, just like in the tangential surfaces, the specimens bonded with PVAc exhibited a higher shear strength compared with those glued with PU. According to these results, it is definitely necessary to sand the surfaces prior to the bonding process to have a higher shear strength. The bonding process should be made on the tangential surfaces with higher pressures. The PVAc adhesive should be preferred instead of the PU adhesive. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3050–3061, 2006
Rubber‐toughened polypropylene nanocomposite: Effect of polyethylene octene copolymer on mechanical properties and phase morphology
Authors: Lim J. W. , Hassan A. , Rahmat A. R. , Wahit M. U.
Published: January 2006

Rubber‐toughened polypropylene (PP)/org‐Montmorillonite (org‐MMT) nanocomposite with polyethylene octene (POE) copolymer were compounded in a twin‐screw extruder at 230°C and injection‐molded. The POE used had 25 wt % 1‐octene content and the weight fraction of POE in the blend was varied in the range of 0–20 wt %. X‐ray diffraction analysis (XRD) revealed that an intercalation org‐MMT silicate layer structure was formed in rubber‐toughened polypropylene nanocomposites (RTPPNC). Izod impact measurements indicated that the addition of POE led to a significant improvement in the impact strength of the RTPPNC, from 6.2 kJ/m2 in untoughened PP nanocomposites to 17.8 kJ/m2 in RTPPNC containing 20 wt % POE. This shows that the POE elastomer was very effective in converting brittle PP nanocomposites into tough nanocomposites. However, the Young's modulus, tensile strength, flexural modulus, and flexural strength of the blends decreased with respect to the PP nanocomposites, as the weight fraction of POE was increased to 20 wt %. Scanning electron microscopy (SEM) was used for the investigation of the phase morphology and rubber particles size. SEM study revealed a two‐phase morphology where POE, as droplets was dispersed finely and uniformly in the PP matrix. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3441–3450, 2006
Preparation of electrorheological active ionomers from poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine)
Authors: Yilmaz Hasim , Unal Halil Ibrahim
Published: January 2006

In this study, synthesis, characterization, partial hydrolysis, and salt formation of poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine), (poly(HEMA)‐co‐poly‐(4‐VP)) copolymers were investigated. The copolymers were synthesized by free radical polymerization using K2S2O8 as an initiator. By varying the monomer/initiator ratio, chain lengths of the copolymers were changed. The copolymers were characterized by gel permeation chromatography (GPC), viscosity measurements, 1H and 13C NMR and FTIR spectroscopies, elemental analysis, and end group analysis methods. The copolymers were partially hydrolyzed by p‐toluene sulfonic acid monohydrate (PTSA·H2O) and washed with LiOH(aq) solution to prepare electrorheological (ER) active ionomers, poly(Li‐HEMA)‐co‐poly(4‐VP). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3540–3548, 2006
Effects of fiber aggregates on the transverse mechanical behavior of commingled PP–glass fiber composites
Authors: Dubouloz‐Monnet F. , Albérola N. D. , Mélé P.
Published: January 2006

In previous articles, mechanical models were proposed to predict the reinforcement effect of polymers by particulates as well as unidirectional fibers over wide ranges of volume fraction of fillers and temperatures. On the basis of image analyses and the definition of representative morphological motifs, these models are able to predict the viscoelastic properties of quasi‐isotropic and unidirectional composites or to extract the behavior of a phase, such as the interphase in filled rubbers or the transcrystalline phase in semicrystalline polymers. In this work, based on a 2D image processing, this approach is extended to predict the viscoelastic properties of commingled PP–glass fiber composites. It is shown that fiber aggregates, composed of fibers and surrounding polymer, might be considered as the reinforcing phase. In addition, the different failure modes of these composites are separated as a function of the volume fraction of fillers or temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3466–3476, 2006
Gas diffusion in branched and crosslinked polymers: A model of treelike clusters
Authors: Khalikov R. M. , Kozlov G. V. , Zaikov G. E.
Published: January 2006

The correctness of the fractal model of treelike clusters for describing the diffusion processes in branched (crosslinked) copolymers is shown. As in the fractal model of gas transport processes, for the copolymers investigated, the main role of diffusivity was to change the connectivity of the macromolecule, characterized by its spectral dimension. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3571–3573, 2006
Effect of magnesium and phosphate ions on the stability of concentrated natural rubber latex and the properties of natural rubber latex–dipped products
Authors: Karunanayake L. , Perera G. M. Priyanthi
Published: January 2006

The presence of Mg2+ ions was found to be a major cause of destabilization of natural rubber (NR) latex. On the other hand, the addition of excess PO ions to remove Mg2+ ions could adversely affect the physical properties of dipped products made of NR latex. A series of concentrated latex samples were treated with varying amounts of Mg2+ and PO ions. Changes with time in the characteristics of the treated latex samples such as mechanical stability time, volatile fatty acid number, and chemical stability time and in the physical properties of the dipped products such as aged and unaged tensile properties were monitored. The latex batch with a PO ion concentration of 30 ppm was found to produce the best‐quality latex and dipped products. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3120–3124, 2006
Enhancement of the optical properties of poly vinyl alcohol by doping with silver nanoparticles
Authors: Badr Y. , Mahmoud M. A.
Published: January 2006

Poly vinyl alcohol (PVA) incorporated with different weight percent of Silver nanoparticles (Ag NPs) were prepared. The enhancement factors for each band in the Raman spectra were calculated and the degree of enhancement were found to be increased as the percent of Ag NPs increases up to 0.3%, and thereafter it decreases. Some bands were red shifted while others were blue shifted. The overtones FTIR bands and photoacoustic spectra were recorded and show the same behavior as those bands. The X‐ray diffraction pattern and Raman and photoacoustic spectra showed that PVA has a high degree of crystallinity. The UV–vis spectra of the same samples were red shifted and increase in their intensities up to 0.3% Ag NPs, thereafter the band intensities of the peak corresponding to Ag NPs were diminished. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3608–3614, 2006
Effect of a fatty amine on processing and physical properties of SBR compounds filled with silane–silica particles
Authors: Valentín J. L. , Posadas P. , Marcos‐Fernández A. , Ibarra L. , Rodríguez A.
Published: January 2006

The use of fatty amines, obtained from natural fatty acids, in rubber compounds to improve silica dispersion was evaluated. Fatty amines can interact with the free silanol groups of the bis(3‐triethoxysilyl‐propyl) tetrasulfide (TESPT) silane‐modified silica forming an amine‐modified silica complex, which reduces the hydrophilic nature of the silica surface, minimizing the silica–silica interactions, and reducing the formation of secondary structures of silica. The effect of the addition of different amines and/or polyethylenglycol to SBR compounds loaded with silane‐modified silica was evaluated. Finally, incorporation of fatty amines improved the processability and traction properties of rubber compounds loaded with modified silica. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3222–3229, 2006
Synthesis and characterization of poly(butyl acrylate)/silica and poly(butyl acrylate)/silica/poly(methyl methacrylate) composite particles
Authors: Qi Dong‐Ming , Bao Yong‐Zhong , Huang Zhi‐Ming , Weng Zhi‐Xue
Published: January 2006

Poly(butyl acrylate)/poly(methyl methacrylate) (PBA/PMMA) core–shell particles embedded with nanometer‐sized silica particles were prepared by emulsion polymerization of butyl acrylate (BA) in the presence of silica particles preabsorbed with 2,2′‐azobis(2‐amidinopropane)dihydrochloride (AIBA) initiator and subsequent MMA emulsion polymerization in the presence of PBA/silica composite particles. The morphologies of the resulting PBA/silica and PBA/silica/PMMA composite particles were characterized, which showed that AIBA could be absorbed effectively onto silica particles when the pH of the dispersion medium was greater than the isoelectric potential point of silica. The critical amount of AIBA added to have stable dispersion of silica particles increased as the pH of the dispersion medium increased. PBA/silica composite particles prepared by in situ emulsion polymerization using silica preabsorbed with AIBA showed higher silica absorption efficiency than did the PBA/silica composite particles prepared by direct mixing of PBA latex and silica dispersion or by emulsion polymerization in which AIBA was added after the mixing of BA and silica. The PBA/silica composite particles exhibited a raspberrylike morphology, with silica particles “adhered” to the surfaces of the PBA particles, whereas the PBA/silica/PMMA composite latex particles exhibited a sandwich morphology, with silica particles mainly at the interface between the PBA core and the PMMA shell. Subsequently, the PBA/silica/PMMA composite latex obtained had a narrow particle size distribution and good dispersion stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3425–3432, 2006
Effects of particle size on the molecular orientation and birefringence of magnetic nanoparticles/polyimide composites
Authors: Kang Jin Ho , Kim Young Chul , Cho Kilwon , Park Chan Eon
Published: January 2006

Size dependency of nanoparticles for birefringence and molecular orientation of nanocomposite films have been studied using a prism coupler and near‐edge X‐ray absorption fine structure spectroscopy (NEXAFS). We synthesized two different sizes of magnetic nanoparticles, Ni0.6Zn0.4Fe2O4. The smaller ones were 6.1 ± 1.3 nm‐diameter nanoparticles showing superparamagnetism and the larger ones were 20.7 ± 6.1 nm‐diameter nanoparticles showing ferrimagnetism. To make nanocomposites, we incorporated these particles into poly(N,N′‐bis(phenoxyphenyl)pyromellitimide) (PMDA‐ODA PI). From the prism coupler study, pristine PI without nanoparticles had higher out‐of‐plane birefringence, which indicated high in‐plane orientation of polyimide. However, the birefringence of PI nanocomposites decreased with the increase of particle content. The birefringence of PI nanocomposite with small nanoparticles was smaller than that of PI nanocomposite with large nanoparticles. The birefringence of PI nanocomposite with 1 wt % of small nanoparticles was reduced to almost half of that of pristine PI due to the decreased orientation of PI molecules. NEXAFS spectra of N K‐edge were the same as the birefringence results. Imide and phenyl rings of pristine PI aligned more parallel to the in‐plane direction, but those of PI with nanoparticles aligned less parallel to the in‐plane direction. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3433–3440, 2006
Structure and properties of polybutadiene/montmorillonite nanocomposites prepared by in situ polymerization
Authors: Liao Mingyi , Zhang Weiqing , Shan Wei , Zhang Yipeng
Published: January 2006

Polybutadiene (PB)/Montmorillonite nanocomposites (NCs) were prepared by in situ polymerization through the anionic polymerization technique. The effects of treating method of organophilic MMT (OMMT), the type of OMMT, and the solvent used in polymerization were studied. The structure and properties of NCs were characterized using X‐ray Diffraction (XRD), transmission electron micrograph (TEM), H‐NMR spectrum, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The consumption of BuLi was varied with different treating methods. The molecular weight distribution of PB added with OMMT (DK1) was wide, and the molecular weight distribution became narrow when OMMT‐DK1B and DK4 were added. OMMT did not disperse stably in cyclohexane, but could form a homogeneous solution in toluene and xylene. XRD and TEM showed that exfoliated NCs were obtained by in situ polymerization through the anionic polymerization technique. From the H‐NMR spectrum of PB and PB/OMMT NCs, it could be seen that the content of 1, 2 units of PB increased ∼100%, while 1, 4 units decreased when 6.2 wt % of OMMT was added. The results of DSC and DMA indicated that Tg and Tdc were increased when compared with those of PB. Both storage modulus and loss modulus were increased with the addition of OMMT, and tan δ was decreased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3615–3621, 2006
Synthesis and physicochemical characterization of amphiphilic block copolymer self‐aggregates formed by poly(ethylene glycol)‐block‐poly(ϵ‐caprolactone)
Authors: Choi Changyong , Chae Su Young , Kim Tai‐Hyoung , Kweon Jung Keon , Cho Chong Su , Jang Mi‐Kyeong , Nah Jae‐Woon
Published: January 2006

Diblock copolymers with different poly(ε‐caprolactone) (PCL) block lengths were synthesized by ring‐opening polymerization of ε‐caprolactone in the presence of monomethoxy poly(ethylene glycol) (mPEG‐OH, MW 2000) as initiator. The self‐aggregation behaviors and microscopic characteristics of the diblock copolymer self‐aggregates, prepared by the diafiltration method, were investigated by using 1H NMR, dynamic light scattering (DLS), and fluorescence spectroscopy. The PEG–PCL block copolymers formed the self‐aggregate in an aqueous environment by intra‐ and/or intermolecular association between hydrophobic PCL chains. The critical aggregation concentrations of the block copolymer self‐aggregate became lower with increasing hydrophobic PCL block length. On the other hand, reverse trends of mean hydrodynamic diameters were measured by DLS owing to the increasing bulkiness of the hydrophobic chains and hydrophobic interaction between the PCL microdomains. The partition equilibrium constants (Kv) of pyrene, measured by fluorescence spectroscopy, revealed that the inner core hydrophobicity of the nanoparticles increased with increasing PCL chain length. The aggregation number of PCL chain per one hydrophobic microdomain, investigated by the fluorescence quenching method using cetylpyridinium chloride as a quencher, revealed that 4–20 block copolymer chains were needed to form a hydrophobic microdomain, depending on PCL block length. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3520–3527, 2006
Adhesion interactions between poly(vinyl alcohol) and iron‐oxide surfaces: The effect of acetylation
Authors: Uner B. , Ramasubramanian M. K. , Zauscher S. , Kadla J. F.
Published: January 2006

Atomic force microscopy with chemically functionalized colloidal probes was used to study “acid–base” interactions between poly(vinyl alcohol) (PVA) and a metal surface. By using well‐defined model surfaces, we have studied the adhesion forces between a hydroxylated surface and cantilever tips with varying hydroxyl content. Decreasing the amount of available hydroxyl groups dramatically reduced the observed adhesion force. The calculated bond energy for each cantilever tip was found to be in the range of typical hydrogen bond energies, i.e., 10–40 kJ/mol, suggesting that the acid–base interactions are predominately hydrogen bonding. Similarly, the force versus distance curves using PVA functionalized colloidal probes showed a strong dependence on the chemical functionality of the tip and the degree of acetylation of the intervening PVA. It was observed that, with an increase in the acetyl content of the PVA, the adhesion force decreased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3528–3534, 2006
Cyanuric acid–epichlorohydrin prepolymers
Authors: Pedroso L. M. , Simões P. , Portugal A.
Published: January 2006

In this study, we investigated the reaction of cyanuric acid and epichlorohydrin (ECH). SnCl4was used as a catalyst. Several reaction conditions were tested, and the products were analyzed by means of Fourier transform infrared and1H‐NMR spectroscopy, hydroxyl group content, molar mass, elemental and thermal analysis, viscosity, and density. ECH reacted with the amine groups of the cyanuric acid ring to form lateral chains that contained chloroalkyl and hydroxyl end groups. Full substitution of the amine groups was observed in all of the synthesized products. The solvent used in the synthesis was found to be very important for the structure of the final prepolymers. WhenN,N‐dimethylformamide was used, relatively low‐molar‐mass prepolymers of cyanuric acid and ECH were obtained. When solvents with low dielectric constants were used, no reaction with cyanuric acid was observed. The prepared prepolymers were thermally stable up to 160°C. At this temperature, degradation started via the lateral chains. The viscosity of the products decreased as the ECH–cyanuric acid ratio increased, whereas the density remained basically constant. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3684–3691, 2006
Structural Comparison of Self‐Organized Adlayers of Ligands and Their Metal‐Coordinated Complexes on a Au(111) Surface: An STM Study
Authors: Yuan Qun‐Hui , Wan Li‐Jun
Published: January 2006

Scanning tunneling microscopy (STM) was employed to investigate the adsorption of the linear‐spacer‐bridged ligands bis(pyrrol‐2‐yl‐methyleneamine) (BPMB and BPMmB), and their ZnII‐coordinated complexes, BPMB/ZnII and BPMmB/ZnII, onto a Au(111) surface in 0.1 M HClO4 solution. Both the ligands, with different spacer bridges, and their ZnII complexes adsorb onto the Au(111) surface and self‐organize into highly ordered two‐dimensional arrays. The complexes BPMB/ZnII and BPMmB/ZnII appear in helical and triangular conformations, respectively, consistent with their chemical structures. Although the metal complexes include ligands, the assembled structures and adlayer symmetries of the ligands and complexes are totally different. The structures and intramolecular features obtained by high‐resolution STM imaging are discussed. The results should be important in fabricating surface supramolecular structures.
Spectroscopic Evidence for a Dinitrogen Complex of Gallium and Estimation of the Ga—N2 Bond Strength.
Authors: Himmel Hans‐Joerg , Hebben Nicole
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
A New Hexagonal Modification of AgNiO2.
Authors: Soergel Timo , Jansen Martin
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
The Crystal Structure of Disodium Phosphonate, Na2HPO3.
Authors: Sofina Natalia , Dinnebier Robert , Jansen Martin
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Spatially Resolved Raman and UV‐Visible‐NIR Spectroscopy on the Preparation of Supported Catalyst Bodies: Controlling the Formation of H2PMo11CoO405‐ Inside Al2O3 Pellets During Impregnation.
Authors: Bergwerff Jaap A. , van de Water Leon G. A. , Visser Tom , de Peinder Peter , Leliveld Bob R. G. , de Jong Krijn P. , Weckhuysen Bert M.
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Polyoxometalate‐Supported Y‐ and YbIII‐Hydroxo/Oxo Clusters from Carbonate‐Assisted Hydrolysis.
Authors: Fang Xikui , Anderson Travis M. , Benelli Cristiano , Hill Craig L.
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Convenient Synthesis of Fluorinated Alkanes and Cycloalkanes by Hydrogenation of Perfluoroalkylalkenes under Ultrasound Irradiation.
Authors: Carcenac Y. , Tordeux M. , Wakselman C. , Diter P.
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Lewis Acid Promoted Reactions of γ,γ‐Dialkoxyallylic Zirconium Species with Various Carbonyl Compounds.
Authors: Ito Hisanaka , Sato Azusa , Taguchi Takeo
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Cyclopropyl Building Blocks for Organic Synthesis. Part 120. [5 + 1] Cocyclization of (Cyclopropylmethylene)cyclopropanes and Other Vinylcyclopropanes with Carbon Monoxide Catalyzed by Octacarbonyldicobalt.
Authors: Kurahashi Takuya , de Meijere Armin
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Facile One‐Pot Preparation of [Hydroxy(sulfonyloxy)iodo]arenes from Iodoarenes with MCPBA in the Presence of Sulfonic Acids.
Authors: Yamamoto Yukiharu , Togo Hideo
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Copper Salt Catalyzed Addition of Arylboronic Acids to Azodicarboxylates.
Authors: Uemura Takeshi , Chatani Naoto
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Rhodium‐Catalyzed Alkylation of Terephthaldialdimine with Terminal Alkenes via C—H Bond Activation.
Authors: Lim Yeong‐Gweon , Koo Bon Tak
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Aqueous Solvents Dictate the Regiochemistry in the Photooxidations of α,β‐Unsaturated Carboxylic Acid Salts.
Authors: Stensaas Kristina L. , Bajaj Anisha
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Facile Synthesis of 2‐Alkynyl Buta‐1,3‐dienes via Sonogashira Cross‐Coupling Methodology.
Authors: Shao Li‐Xiong , Shi Min
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Thermal Reactions of 8‐Methylbicyclo[4.2.0]oct‐2‐enes: Competitive Diradical‐Mediated [1,3] Sigmatropic, Stereomutation, and Fragmentation Processes.
Authors: Bogle Xavier S. , Leber Phyllis A. , McCullough Lynne A. , Powers David C.
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Synthesis of Highly Functionalized Spiro‐Indoles by a Halogen Atom Transfer Radical Cyclization.
Authors: Stevens Christian V. , Van Meenen Ellen , Eeckhout Yves , Vanderhoydonck Bart , Hooghe Wim
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Reversible Rearrangement of 1,2,3‐Triazole‐4‐carbothioamide to 1,2,3‐Thiadiazole‐4‐carbimines.
Authors: Glukhareva T. V. , Dyudya L. V. , Pospelova T. A. , Bakulev V. A. , Tkachev A. V. , Morzherin Yu. Yu.
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Regioselective Synthesis and Estrogenicity of (.+‐.)‐8‐Alkyl‐5,7‐dihydroxy‐4‐(4‐hydroxyphenyl)‐3,4‐dihydrocoumarins.
Authors: Roelens Frederik , Huvaere Kevin , Dhooge Willem , Van Clemput Marjan , Comhaire Frank , De Keukeleire Denis
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Synthesis and Characterization of Some New 4,4′‐(1,4‐Phenylene)dipyrimidine and 6,6′‐(1,4‐Phenylene)‐di(pyridin‐2(1H)‐one) Derivatives.
Authors: Shaker Raafat M.
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Palladium‐Catalyzed Allylic Transposition of (Allyloxy) Iminodiazaphospholidines: A Formal [3,3]‐Aza‐phospha‐oxa‐Cope Sigmatropic Rearrangement for the Stereoselective Synthesis of Allylic Amines.
Authors: Lee Ernest E. , Batey Robert A.
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Unique Reactivity of α‐Alkoxy Ginkgolide Lactones to Nucleophilic Reagents: Preparation of New Lactol Derivatives.
Authors: Tanaka Katsunori , Pimentel Marc , Berova Nina , Nakanishi Koji
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.
Three New Polyoxypregnane Glycosides from Marsdenia tenacissima.
Authors: Deng Jun , Liao Zhixin , Chen Daofeng
Published: January 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF.