bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of polyvinylsilicone oil with condensed aromatics on the radiation resistance of heat‐curable silicone rubber
Authors: Jiang Zhigang , Zhang Jie , Feng Shengyu 
Published: July 2006

AbstractPolyvinylsilicone oil with condensed aromatics (called C1 gum) was synthesized by Diels‐Alder reaction of polyvinylsilicone oil and acenaphthenecyclone, and was used as an additive in heat‐curable silicone rubber. The resistance to irradiation of the silicone rubber obtained was investigated by γ‐rays at doses up to 300, 500, and 1000 kGy in vacuum. The dose rate was 150 kGy/min. After irradiation, the average molecular weight between crosslinks (Mc) and mechanical properties of the silicone rubber were determined. The results show that C1 gum can effectively improve the radiation resistance of silicone rubber. When the amount of C1 gum used in silicone rubber changes from 2 to 14 parts per hundred silicone gum, the radiation protection effects increase with increasing amount of C1 gum. The radiation protection mechanism of C1 gum was also discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1937–1942, 2006
Adhesion of glass/epoxy composites influenced by thermal and cryogenic environments
Authors: Ray Bankim C. 
Published: July 2006

AbstractLittle information regarding the effects of prior thermal and cryogenic conditionings on hydrothermal and mechanical behavior, for varied volume fractions of constituent phases in polymer matrix fiber composites, has been published to date. The present experimental investigation uses flexural test to assess the effects of thermal and cryogenic treatments, and concurrently followed hydrothermal aging on quality of adhesion of multilayered laminates for 55, 60, and 65 wt % of E‐glass fiber‐reinforced epoxy composites. The specimens were conditioned at 80°C and −80°C temperatures for different time durations, and thereafter they were immediately immersed in boiling water for an hour. Water absorption rates were evaluated for those conditioned specimens in such environment. Absorption study in hydrothermal aging showed a remarkable variation for the two cases of prior conditionings. The shear strength values were compared with the test value of as‐cured samples. Degradation of mechanical property was found to be less prevalent during hydrothermal aging, with a prior conditioning at 80°C temperature compared to −80°C treated glass/epoxy composites. Improved shear strength for almost all conditions of thermal conditioning in the initial stages has highlighted better adhesion influenced by postcuring phenomena during thermal or cryogenic conditioning. It was also observed from water absorption data that high temperature conditioning contributed more strengthening effect and better adhesion at the interfaces. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1943–1949, 2006
Stiffening agent for cotton woven fabrics made from methacrylic acid vinyl acetate methylacrylate terpolymer
Authors: Moustafa A. F. 
Published: July 2006

AbstractThe emulsion polymerizations of methacrylic acid (MAA), vinyl acetate (VAc), and methyl acrylate (MA) in different VAc/MA molar concentrations (X1, 0.232/0.813; X2, 0.348/0.697; X3, 0.456/0.581; X4, 0.581/0.465; X5, 0.697/0.348) and fixed MAA concentration (0.116 mol) were carried out using sodium dodecyl sulfate (SDS; 34 mmol) as emulsifier and potassium persulphate (K2S2O8; 37 mmol) as initiator at 70 °C for 6 h in semicontinuous reaction mode. The average molecular weights (Mn,Mw) and the molecular weights distributions were determined using gel permeation chromatography (GPC). All terpolymers prepared showed monomodal molecular weights distributions. Glass transition (Tg), crystallization (Tc), and melting (Tm) temperatures and thermal stability of the prepared terpolymers were determined using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), respectively. The elongation percentage at rupture, tensile strength and accelerated thermal aging were determined for X1–5terpolymers, as functions of the molar composition in the emulsion polymerization feed. The terpolymers prepared, X1–5terpolymers, were tested as stiffening agents for cotton woven fabrics through crosslinking to cellulose, using sodium hypophosphite monohydrate (NaH2PO2·H2O) as catalyst. The effect of X1–5compositions upon the stiffening efficiency was discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 2006
Melting aspects of filled compounds in a modular co‐rotating twin screw extruder
Authors: Jung Hochul , White James L. 
Published: July 2006

AbstractIn the polymer industry, precompounded materials are widely used. Carefully designed melting experiments were carried out to investigate melting mechanisms in master batched polymer compounds, using an intermeshing co‐rotating twin screw extruder. Calcium carbonate or aluminum powder was master batched with linear low‐density polyethylene (LLDPE). The calcium carbonates, which were used in the compounds, have differences in weight fraction and particle size. The compounds containing filler have higher thermal conductivities and viscosities than neat polyethylene. We observed melting initiation and propagation mechanisms of LLDPE compounds by removal and characterization of polymer compound carcasses in the melting region. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1990–2012, 2006
Performance of pineapple leaf fiber–natural rubber composites: The effect of fiber surface treatments
Authors: Lopattananon Natinee , Panawarangkul Kuljanee , Sahakaro Kannika , Ellis Bryan 
Published: July 2006

AbstractComposites of natural rubber (NR) and short pineapple leaf fiber (PALF) were prepared on a laboratory two‐roll mill. The influences of untreated fiber content and orientation on the processing and mechanical properties of the composites were investigated. The dependence of extent of orientation on fiber concentration was also established. Sodium hydroxide (NaOH) solutions (1, 3, 5, and 7% w/v) and benzoyl peroxide (BPO) (1, 3, and 5 wt % of fiber) were used to treat the surfaces of PALFs. FTIR and scanning electron microscope (SEM) observations were made of the treatments in terms of chemical composition and surface structure. The tensile strength and elongation at break of the composites were later studied. The fiber–matrix adhesion was also investigated using SEM technique. It was found that all surface modifications enhanced adhesion and tensile properties. The treatments with 5% NaOH and 1% BPO provided the best improvement of composite strength (28 and 57% respectively) when compared with that of untreated fiber. The PALF‐NR composites also exhibited better resistance to aging than its gum vulcanizate, especially when combined with the treated fibers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1974–1984, 2006
Studies on the diffusion characteristics of some aromatic solvents into polypropylene film
Authors: Igwe Isaac O. , Ewulonu Chinomso M. , Igboanugo Ifeoma 
Published: July 2006

AbstractThe sorption properties of the solvents benzene, toluene, and xylene into polypropylene films at 40, 60, and 80°C have been investigated. The diffusivity and permeability of the solvents into polypropylene films were found to increase in the order of solvent, benzene, toluene, and xylene at the different temperatures studied. The properties were also found to be temperature dependent. The zsolubility of the solvents into polypropylene films was found to be highest in toluene, followed by xylene, and least in benzene. However, a general increase in solubility with temperature was observed for all the solvents studied. The calculated values of activation energy of diffusion did not show any relationship with solvent properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1985–1989, 2006
Oxidative status and serum leptin levels in obese prepubertal children
Authors: Ustundag Bilal , Gungor Serdal , Aygün A. Denizmen , Turgut Mehmet , Yilmaz Erdal 
Published: July 2006

AbstractThe prevalence of obesity in children has increased dramatically over the last 20–30 years in developed countries. The aim of this study was to evaluate the oxidative and antioxidant status and any correlation with leptin in obese prepubertal children. A cross‐sectional study was made of healthy children from ten elementary schools in the province of Elazig, Eastern Turkey. Blood samples were drawn from children comprising obese and control groups, on a visit to their school in the morning after an overnight fast. The mean body mass index (BMI) was 24.03 ± 4.09 kg/m2in the obese group and was 17.51 ± 2.33 kg/m2in the control group. Mean plasma leptin concentration was significantly higher in the obese children. Homocysteine and malondialdehyde (MDA) levels were also significantly higher in the obese group. In contrast superoxide dismutase (SOD) and glutathione peroxidase activities were significantly decreased in the obese group (p < 0.001). In conclusion, in prepubertal obese children oxidative stress was increased and MDA and homocysteine levels were well correlated with serum leptin level and BMI. In contrast with the increase in oxidative stress, antioxidant activities of SOD and glutathione peroxidase were decreased in obese prepubertal children. Copyright © 2006 John Wiley & Sons, Ltd.
A Range of Spin‐Crossover Temperature T1/2>300 K Results from Out‐of‐Sphere Anion Exchange in a Series of Ferrous Materials Based on the 4‐(4‐Imidazolylmethyl)‐2‐(2‐imidazolylmethyl)imidazole (trim) Ligand, [Fe(trim)2]X2 (X=F, Cl, Br, I): Comparison of Experimental Results with Those Derived from Density Functional Theory Calculations
Authors: Lemercier Gilles , Bréfuel Nicolas , Shova Sergiu , Wolny Juliusz A. , Dahan Françoise , Verelst Marc , Paulsen Hauke , Trautwein Alfred X. , Tuchagues Jean‐Pierre 
Published: July 2006

AbstractThe synthesis and characterization of [FeII(trim)2]Cl2 (2), [FeII(trim)2]Br2⋅MeOH (3), and [FeII(trim)2]I2⋅MeOH (4), including the X‐ray crystal structure determinations of 2 (50 and 293 K) and 4 (293 K), have been performed and their properties have been examined. In agreement with the magnetic susceptibility results, the Mössbauer data show the presence of high‐spin (HS) to low‐spin (LS) crossover with a range of T1/2 larger than 300 K (from ≈20 K for [FeII(trim)2]F2 (1) to ≈380 K for 4). All complexes in this series include the same [Fe(trim)2]2+ complex cation: the ligand field comprises a constant contribution from the trim ligands and a variable one originating from the out‐of‐sphere anions, which is transmitted to the metal center by the connecting imidazole rings and hydrogen bonds. The impressive variation in the intrinsic characteristics of the spin‐crossover (SCO) phenomenon in this series is then interpreted as an inductive effect of the anions transmitted to the nitrogen donors through the hydrogen bonds. Based on this qualitative analysis, an increased inductive effect of the out‐of‐sphere anion corresponds to a decreased SCO temperature T1/2, in agreement with the experimental results. Electronic structure calculations with periodic boundary conditions have been performed that show the importance of intermolecular effects in tuning the ligand field, and thus in determining the transition temperature. Starting with the geometries obtained from the X‐ray studies, the [FeII(trim)2]X2 complex molecules 1–4 have been investigated both for the single molecules and the crystal lattices with the local density approximation of density functional theory. The bulk geometries of the complex cations deduced from the X‐ray studies and those calculated are in fair agreement for both approaches. However, the trend observed for the transition temperatures of 1–4 disagrees with the trend for the spin‐state splittings ES (difference EHS−ELS between the energy of the HS and LS isomers) calculated for the isolated molecules, whereas it agrees with the trend for ES calculated with periodic boundary conditions. The latter calculations predict the strongest stabilization of the HS state for the fluoride complex, which actually is essentially HS above T=50 K, while the most pronounced stabilization of the LS state is predicted for 4, in line with the experimental results.
Identity SN2 Reactions X−+CH3X→XCH3+X− (X=F, Cl, Br, and I) in Vacuum and in Aqueous Solution: A Valence Bond Study
Authors: Song Lingchun , Wu Wei , Hiberty Philippe C. , Shaik Sason 
Published: July 2006

AbstractThe recently developed (L. Song, W. Wu, Q. Zhang, S. Shaik, J. Phys. Chem. A 2004, 108, 6017) valence bond method coupled with a polarized continuum model (VBPCM) has been applied to the identity SN2 reaction of halides in the gas phase and in aqueous solution. The barriers computed at the level of the breathing orbital VB method (P. C. Hiberty, J. P. Flament, E. Noizet, Chem. Phys. Lett. 1992, 189, 259), BOVB and VBPCM//BOVB, are comparable to CCSD(T) and CCSD(T)//PCM results and to experimentally derived barriers in solution (W. J. Albery, M. M. Kreevoy, Adv. Phys. Org. Chem. 1978, 16, 85). The reactivity parameters needed to apply the valence bond state correlation diagram (VBSCD) method (S. Shaik, J. Am. Chem. Soc. 1984, 106, 1227), were also determined by VB calculations. It has been shown that the reactivity parameters along with their semiempirical derivations provide a satisfactory qualitative and quantitative account of the barriers.
Self‐Assembly and Liquid‐Crystalline Properties of 5‐Fluoroalkylporphyrins
Authors: Jin Li‐Mei , Yin Juan‐Juan , Chen Liang , Zhou Jin‐Ming , Xiao Ji‐Chang , Guo Can‐Cheng , Chen Qing‐Yun 
Published: July 2006

AbstractWe report three crystal structures of a synthetic 5‐fluoroalkylporphyrin molecule that was programmed for self‐assembly. All the X‐ray structures of zincated and free‐base porphyrins Zn2 b, Zn5 a, and 2 b revealed rigorous π–π stacking and extremely hydrophobic interactions. Other the other hand, the strong aggregation of 5‐fluoroalkylporphyrins in solution was also found. Interestingly, the regular nanopore formation of the 5‐fluoroalkylporphyrin was visualized by atomic force microscopy (AFM). Importantly, the 5‐fluoroalkylporphyrins possess liquid‐crystalline properties that were confirmed by using a combination of differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) techniques. By comparison, the self‐assembly of non‐fluorine‐containing porphyrins with similar structure showed much lower aggregation ability, as investigated by NMR techniques. Additionally, no birefringent mesophase was observed for the non‐fluorine‐containing porphyrin.
Structure and Reactivity of Radical Ions: New Twists on Old Concepts
Authors: Donoghue Patrick J. , Wiest Olaf 
Published: July 2006

AbstractElectron transfer is the simplest reaction possible, yet it has a profound impact on the structure and reactivity of organic compounds. These changes allow a new look at some of the fundamental concepts that are used to explain organic chemistry, such as symmetry, aromaticity, and bonding. The results from high‐level electronic structure calculations are used to analyze the mechanistic differences in the pericyclic reactions of simple hydrocarbons and their radical cation counterparts. The importance of state symmetry correlation, Jahn–Teller distortions, delocalization, and fractional bonding for the reaction pathways of hydrocarbon radical cations is discussed.
A Synthetic Breakthrough into an Unanticipated Stability Regime: A Series of Isolable Complexes in which C6, C8, C10, C12, C16, C20, C24, and C28 Polyynediyl Chains Span Two Platinum Atoms
Authors: Zheng Qinglin , Bohling James C. , Peters Thomas B. , Frisch Anja C. , Hampel Frank , Gladysz J. A. 
Published: July 2006

AbstractThe reaction of trans‐[PtCl(p‐tol){P(p‐tol)3}2] (PtCl) and H(CC)2H (cat. CuI, HNEt2) gives PtC4H (82 %), which can be cross‐coupled with excess HCCSiEt3 (acetone, O2, CuCl/TMEDA; Hay conditions) to yield PtC6Si (77 %). The addition of nBu4N+F− in wet acetone gives PtC6H (84 %), and further addition of ClSiMe3 (F− scavenger) and excess HCCSiEt3 (Hay conditions) yields PtC8Si (23 %). Similar cross‐coupling reactions of PtCxH (generated in situ for x>6) and excess H(CC)2SiEt3 give a) x=4, PtC8Si (29 %), PtC12Si (30 %), and PtC16Si (1 %); b) x=6, PtC10Si (59 %) and PtC14Si (7 %); c) x=8, PtC12Si (42 %); and d) x=10, PtC14Si (20 %). Hay homocoupling reactions of PtC4H, PtC6H, PtC8H, and PtC10H give PtC8Pt, PtC12Pt, PtC16Pt, and PtC20Pt (88–70 %), but PtC12H decomposes too rapidly. However, when PtC12Si and PtC14Si are subjected to Hay conditions, protodesilylation occurs in the presence of the oxidizing agent and PtC24Pt (36 %) and PtC28Pt (51 %) are isolated. Reactions of PtC6H and PtC10H with PtCl (CuI, HNEt2) give PtC6Pt (56 %) and PtC10Pt (84 %). The effect of the chain lengths in PtCxPt upon thermal stabilities (>200 °C for x≤20), IR νCC patterns (progressively more bands), colors (yellow to orange to deep red), UV/Vis spectra (progressively red‐shifted and more intense bands with ε>400 000 M−1 cm−1), redox properties (progressively more difficult oxidations), and NMR spectra (many monotonic trends) are analyzed, including implications for the sp carbon allotrope carbyne. Whereas all other dodecaynes and tetradecaynes rapidly decompose at room temperature, PtC24Pt and PtC28Pt remain stable at >140 °C. Crystal structures of PtCxSi (x=6, 8, 10) and PtCxPt (x=6, 8, 10, 12) have been determined.
Er5Ni3Al3Ge4: A Quaternary Variant of the NbCoB Type.
Authors: Demchenko Pavlo , Konczyk Joanna , Demchenko Grigorii , Gladyshevskii Roman , Pavlyuk Volodymyr 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Chemical Stability of LiNaSO4 Electrolyte During Operation in a H2—O2 Fuel Cell.
Authors: Feng Yu , Luo Jingli , Chuang Karl T. 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Zirconium Scandium Oxide Nitrides: Formation and Decomposition Followed in situ by XRD and Thermal Analysis.
Authors: Martinez Meta N. J. , Schweda E. 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Syntheses and Crystal Structures of Three New Borates Templated by Transition‐Metal Complexes in situ.
Authors: Wang Guo‐Ming , Sun Yan‐Qiong , Yang Guo‐Yu 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Enantioselective Modular Synthesis of 2,4‐Disubstituted Cyclopentenones by Iridium‐Catalyzed Allylic Alkylation.
Authors: Schelwies Mathias , Duebon Pierre , Helmchen Guenther 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Remote Stereocontrol Using (E)‐6‐Hydroxy‐4‐methylhex‐2‐enyl(tri‐n‐butyl)stannane.
Authors: MacCormick Somhairle , Thomas Eric J. 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Very Simple, Highly Stereoselective and Modular Synthesis of Ferrocene‐Based P‐Chiral Phosphine Ligands.
Authors: Chen Weiping , Mbafor William , Roberts Stanley M. , Whittall John 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Resolution of Racemic 2‐Aminocyclohexanol Derivatives and Their Application as Ligands in Asymmetric Catalysis.
Authors: Schiffers Ingo , Rantanen Toni , Schmidt Frank , Bergmans Werner , Zani Lorenzo , Bolm Carsten 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Highly Enantioselective Addition of Ketones to Nitroolefins Catalyzed by New Thiourea—Amine Bifunctional Organocatalysts.
Authors: Tsogoeva Svetlana B. , Wei Shengwei 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
New Indium‐Mediated Cyclization Reactions of Tethered Haloenynes in Aqueous Solvent Systems.
Authors: Goeta Andres , Salter Matthew M. , Shah Hummad 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Palladium‐Catalyzed Tandem Cyclization—Anion Capture Processes. Part 8. In situ and Preformed Organostannanes. Carbamyl Chlorides and Other Starter Species.
Authors: Anwar Usman , Fielding Mark R. , Grigg Ronald , Sridharan Visuvanathar , Urch Christopher J. 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Bromoiodinanes with an I(III)—Br Bond: Preparation, X‐Ray Crystallography and Reactivity as Electrophilic Brominating Agents.
Authors: Braddock D. Christopher , Cansell Gemma , Hermitage Stephen A. , White Andrew J. P. 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Ionic Liquid Promoted Synthesis of β‐Enamino Ketones at Room Temperature.
Authors: Bhosale Rajesh S. , Suryawanshi Padmakar A. , Ingle Sachin A. , Lokhande Mahendra N. , More Sandeep P. , Mane Sandeep B. , Bhosale Sidthanath V. , Pawar Rajendra P. 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
An Efficient Procedure for the Synthesis of 1,1‐Diacetates from Aldehydes with Acetic Anhydride Catalyzed by Silica Sulfate.
Authors: Jin Tong‐Shou , Zhao Ying , Gu Shu‐Qing , Liu Li‐Bin , Li Tong‐Shuang 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Iron Nanoparticles in the Coupling of Alkyl Halides with Aryl Grignard Reagents.
Authors: Bedford Robin B. , Betham Michael , Bruce Duncan W. , Davis Sean A. , Frost Robert M. , Hird Michael 
Published: July 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Preparation of Trifluoromethylated Ynamines and Their Reactions with Some Electrophilic Reagents.
Authors: Ishihara Takashi , Mantani Toshiya , Konno Tsutomu , Yamanaka Hiroki 
Published: July 2006

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