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1.
Low‐rate dynamic contact angles of 12 liquids on a poly(methyl methacrylate/ethyl methacrylate, 30/70) P(MMA/EMA, 30/70) copolymer were measured by an automated axisymmetric drop shape analysis‐profile (ADSA‐P). It was found that five liquids yield nonconstant contact angles, and/or dissolve the polymer on contact. From the experimental contact angles of the remaining seven liquids, it is found that the liquid–vapor surface tension times cosine of the contact angle changes smoothly with the liquid–vapor surface tension (i.e., γl|Kv cos θ depends only on γl|Kv for a given solid surface or solid surface tension). This contact angle pattern is in harmony with those from other methacrylate polymer surfaces previously studied.45,50 The solid–vapor surface tension calculated from the equation‐of‐state approach for solid–liquid interfacial tensions14 is found to be 35.1 mJ/m2, with a 95% confidence limit of ± 0.3 mJ/m2, from the experimental contact angles of the seven liquids. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2039–2051, 1999 相似文献
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M. Gllstedt J. Trnqvist M. S. Hedenqvist 《Journal of Polymer Science.Polymer Physics》2001,39(10):985-992
Chitosan (chitosan acetic acid salt) and whey (65% protein) films were coated with a nitrocellulose lacquer or laminated with polyethylene to enhance their water resistance and gas barrier properties in humid environments. The barrier properties were measured by the Cobb60 test and water‐vapor (100% relative humidity) transmission and oxygen (90% relative humidity) permeability tests. Mechanical properties were obtained with tensile tests. Packaging properties were studied with crease and folding tests. The Cobb60 test revealed that the coated films were resistant to liquid water, at least for a short exposure time, if the coating thickness was at least 10–17 μm. Water‐vapor transmission rates comparable to those of polyethylene‐laminated films were obtained for coated chitosan at a coating thickness of 5–7 μm. The coated films possessed low oxygen permeability despite the high humidity. Coated films dried for 3 weeks showed oxygen permeabilities at 90% relative humidity that were similar to values for dry ethylene‐co‐vinyl alcohol at 0% relative humidity. The lacquer partly penetrated the whey films, and this led to excellent adhesion but poor lacquer toughness. The lacquer coating on chitosan was tougher, and it was possible to fold these films 90° without the coating fracturing if the coating thickness was small. The coated whey films were readily creasable. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 985–992, 2001 相似文献
4.
Chen‐Chi M. Ma Shang‐Chin Sung Feng‐Yih Wang Long Y. Chiang Lee Y. Wang Chin‐Lung Chiang 《Journal of Polymer Science.Polymer Physics》2001,39(20):2436-2443
Fullerenol polyurethane (C60‐PU) and linear polyurethane (linear‐PU) modified phenolic resins were prepared in this study. Phenolic resin/C60‐PU and phenolic resin/linear‐PU blends show good miscibility as a result of the intermolecular hydrogen bonding existing between phenolic resin and PU modifiers. DSC and thermogravimetric analysis methods were used to study the thermal properties of phenolic resin blended with different types of PUs. The intermolecular hydrogen bonding that existed between phenolic resin and C60‐PU was investigated by Fourier transform infrared spectroscopy. The morphology and mechanical properties of phenolic resin/C60‐PU and phenolic resin/linear‐PU blends were also investigated. The char yield of the modified phenolic resins decreased with increasing PU modifier content. Significant improvement in the toughness of the modified phenolic resins was observed. The improvements of impact strength were 27.4% for the phenolic resin/linear‐PU system and 54.3% for the phenolic resin/C60‐PU system, respectively, both with 3 phr linear‐PU and C60‐PU content. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2436–2443, 2001 相似文献
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L. F. Ruiz P. A. Hervieux J. Hanssen M. F. Politis F. Martín 《International journal of quantum chemistry》2002,86(1):106-113
We present a theoretical study of charge transfer in H++C60 and He2++C60 collisions using an extension of the molecular time‐dependent method of ion–atom collisions. Energy‐correlation diagrams have been evaluated for the corresponding (C60–H)+ and (C60–He)2+ quasi‐molecules. Single and double charge‐transfer cross sections in C60+He2+ collisions are reported for the first time. The results show that double charge‐transfer cross sections are only one order of magnitude smaller than single charge‐transfer cross sections. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001 相似文献
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Lourdes Ventol Valerie Metivaud Laura Bays Raül Benages Miquelngel Cuevas‐Diarte Teresa Calvet Denise Mondieig 《Helvetica chimica acta》2006,89(9):2027-2039
Complementary techniques had to be applied to investigate the binary system tetradecanedioic acid (C14H26O4)–hexadecanedioic acid (C16H30O4), because all the forms observed have the same space group (P21/c; Z = 2). We studied the polymorphism of the two single compounds and of their mixtures by X‐ray powder diffraction, differential‐scanning calorimetry (DSC), infrared spectroscopy (IR), scanning electron microscopy (SEM), and thermo‐optical microscopy (TOM). The two diacids were found to be isopolymorphic. At low temperature, they crystallize in the same ordered C‐form, and, on heating, adopt the ordered Ch‐form, 1° below their melting point. In contrast to similar compounds (unbranched alkanes, alkanols, and fatty acids), the solid–solid and solid–liquid phase‐transition temperatures decrease with increasing chain length. At low temperature, a new monoclinic form, Ci, appears as a result of the disorder of composition in the mixed samples. There are two [C + Ci]‐type solid–solid domains. On heating, the solid domains are related to solid–liquid domains by a peritectic invariant for compositions rich in C14H26O4, and by a eutectic invariant for compositions rich in C16H30O4. At higher temperature, there appears a second peritectic invariant for compositions rich in C14H26O4, together with a metatectic invariant for compositions rich in C16H30O4. All the solid forms observed in this binary system are isostructural. Nevertheless, the equilibrium between them is complex near the melting point, and their miscibility in the solid state is reduced. 相似文献
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Ju Ho Lee Moon Sam Shin Hwayong Kim Ki-Pung Yoo 《The Journal of chemical thermodynamics》2010,42(7):891-899
Lattice fluid can describe a vapor–liquid transition but not a solid–fluid transition. In this work, we propose a simple and analytic term which yields a solid–fluid transition when coupled with a lattice based equation of state (EOS). The proposed term is derived based on the two assumptions that (1) solid can be considered as highly associated phase affected by strong attractive force and (2) this force is distinct from the conventional attractive forces yielding a vapor–liquid transition. To formulate these assumptions, we extend Veytsman statistics by modifying its density dependency. The derived term was combined with a quasi-chemical nonrandom lattice fluid theory (QLF) developed by the authors. The combined model was found to require only two parameters besides 3 QLF parameters for physical properties calculation of three phases. When tested against equilibrium properties of 8 components, the combined model was found to closely reproduce melting pressure, sublimation pressure, and vapor pressure, but underestimate solid density as well as heat of melting at the triple point temperature. It was found that the present approach can yield a solid–liquid transition at all temperatures. 相似文献
8.
Juanjuan Jiang Lei Tian Yiling Huang Yishi Li 《Biomedical chromatography : BMC》2013,27(12):1603-1608
A sensitive, rapid assay method for estimating ivabradine in human plasma has been developed and validated using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive‐ion mode. The procedure involved extraction of ivabradine and the internal standard (IS) from human plasma by solid‐phase extraction. Chromatographic separation was achieved using an isocratic mobile phase (0.1% formic acid–methanol, 60:40, v/v) at a flow rate of 1.0 mL/min on an Aglient Eclipse XDB C8 column (150 × 4.6 mm, 5 µm; maintained at 35°C) with a total run time of 4.5 min. Detection was achieved using an Applied Biosystems MDS Sciex (Concord, Ontario, Canada) API 3200 triple‐quadrupole mass spectrometer. The MS/MS ion transitions monitored were 469–177 for ivabradine and 453–177 for IS. Method validation was performed according to Food and Drug Administration guidelines, and the results met the acceptance criteria. The calibration curve was linear over a concentration range of 0.1–200 ng/mL. The lower limit of quantitation achieved was 0.1 ng/mL. Intra‐ and inter‐day precisions were in the range of 1.23–14.17% and 5.26‐8.96%, respectively. Finally, the method was successfully used in a pharmacokinetic study that measured ivabradine levels in healthy volunteers after a single 5 mg oral dose of ivabradine. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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《Fluid Phase Equilibria》1999,157(2):229-255
Phase equilibria in the NaCl–Na2SO4–H2O system were investigated at 200 and 250 bar for total salt concentrations ranging from 5 to 20 wt.% total salt over temperatures ranging from 320 to 400°C. In addition to providing data for this ternary system, the experiments also added information on the phase behavior of the two binary systems: NaCl–H2O and Na2SO4–H2O. For salt mixture compositions which were rich in sodium sulfate, a solid phase was observed to nucleate from the homogeneous liquid phase. Salt mixture compositions which had a high fraction of sodium chloride exhibited a vapor separation from a homogeneous liquid phase. By fitting curves to the solid–liquid and vapor–liquid separation temperatures, the temperature and composition of a constrained invariant point where liquid, solid salt and vapor are in equilibrium were estimated. These estimates were performed at discrete compositions of 5, 10, 15 and 20 wt.% total salt at pressures of 200 and 250 bar. The temperature and composition of the invariant point increased with increasing pressure following a simple thermodynamic model for boiling point elevation in a nearly ideal solution. 相似文献
10.
Poklis JL Amira D Wise LE Wiebelhaus JM Haggerty BJ Lichtman AH Poklis A 《Biomedical chromatography : BMC》2012,26(11):1393-1398
The disposition of the cannabimimetic naphthalen‐1‐yl‐(1‐pentylindol‐3‐yl)methanone (JWH‐018) in mice following inhalation of the smoke of the herbal incense product (HIP) ‘Buzz’ is presented. A high‐pressure liquid chromatography with electrospray ionization triple quadrupole mass spectrometer (HPLC/MS/MS) method was validated for the analysis of JWH‐018 in the specimens using deuterated Δ9‐tetrahydrocannabinol (d3‐THC) as the internal standard. JWH‐018 was isolated by cold acetonitrile liquid–liquid extraction. Chromatographic separation was performed on a Zorbaz eclipse XDB‐C18 column. The assay was linear from 1 to 1000 ng/mL. Six C57BL6 mice were sacrificed 20 min after exposure to the smoke of 200 mg ‘Buzz’ containing 5.4% JWH‐018. Specimen concentrations of JWH‐018 were: blood, 54–166 ng/mL (mean 82 ± 42 ng/mL); brain, 316–708 ng/g (mean 510 ± 166 ng/g); and liver, 1370–3220 ng/mL (mean 1990 ± 752 ng/mL). The mean blood to brain ratio for JWH‐018 was 6.8 and ranged from 4.2 to 10.9. After exposure, the responses of the mice were consistent with cannabinoid receptor type 1 activity: body temperatures dropped 7.3 ± 1.1 °C, and catalepsy, hyperreflexia, straub tail and ptosis were observed. The brain concentrations and physiological responses are consistent with the hypothesis that the behavioral effects of ‘Buzz’ are attributable to JWH‐018. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
11.
Junlin Yang Hongzhen Lin Shu Wang Yuliang Li Fenglian Bai Daoben Zhu 《Journal of polymer science. Part A, Polymer chemistry》2001,39(22):3981-3988
The fact that C60 is a good acceptor has stimulated interest in covalently linked complexes, including polymers and oligomers. Photoinduced charge transfer in these systems has great potential for use in photovoltaic devices. In this study, an alternating conjugated oligomer of alkylated carbazole and dialkoxyl‐substituted phenylene, with pendant C60 moieties, (PPV‐AFCAR) was prepared and characterized. The excited‐state properties of PPV–AFCAR were investigated with steady‐state spectroscopy and lifetime measurements. After photoexcitation, photoinduced energy transfer from the oligomer chain to the pendant moiety occurred in great proportion, but a charge‐separation process did not. Whether the energy‐transfer process was measurable or not depended on the system temperature. At 77 K, a quantum yield of more than 50% for energy transfer was found by the fitting of a linear combination of the excitation spectra of the precursor oligomer, the alternating conjugated oligomer of alkylated carbazole and dialkoxyl‐substituted phenylene PPV–ACAR, and the absorption spectra of C60. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3981–3988, 2001 相似文献
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Simultaneous determination of four trace estrogens in feces,leachate, tap and groundwater using solid–liquid extraction/auto solid‐phase extraction and high‐performance liquid chromatography with fluorescence detection
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Na Liu Yue‐e Shi Mengyan Li Ting‐di Zhang Song Gao 《Journal of separation science》2015,38(20):3494-3501
A simple and selective high‐performance liquid chromatography method coupled with fluorescence detection was developed for the simultaneous measurement of trace levels of four estrogens (estrone, estradiol, estriol and 17α‐ethynyl estradiol) in environmental matrices. For feces samples, solid–liquid extraction was applied with a 1:1 v/v mixture of acetonitrile and ethyl acetate as the extraction solvent. For liquid samples (e.g., leachate and groundwater), hydrophobic/lipophilic balanced automated solid‐phase extraction disks were selected due to their high recoveries compared to conventional C18 disks. Chromatographic separations were performed on a reversed‐phase C18 column gradient‐eluted with a 45:55 v/v mixture of acetonitrile and water. The detection limits were down to 1.1 × 10?2 (estrone), 4.11 × 10?4 (estradiol), 5.2 × 10?3 (estriol) and 7.18 × 10?3 μg/L (17α‐ethynyl estradiol) at excitation/emission wavelengths of 288/310 nm, with recoveries in the range of 96.9 ± 3.2–105.4 ± 3.2% (n = 3). The method was successfully applied to determine estrogens in feces and water samples collected at livestock farms and a major river in Northeast China. We observed relatively high abundance and widespread distribution of all four estrogens in our sample collections, implying the urgency for a comprehensive and intricate investigation of estrogenic fate and contamination in our researched area. 相似文献
13.
Roger C. Hiorns Pierre Iratçabal Didier Bégué Abdel Khoukh Rémi De Bettignies Jocelyne Leroy Muriel Firon Carole Sentein Hervé Martinez Hugues Preud'homme Christine Dagron‐Lartigau 《Journal of polymer science. Part A, Polymer chemistry》2009,47(9):2304-2317
The stereo‐electronic control over bisadditions of conjugated polymers to fullerene (C60) is explored in the formation of alternating copolymers. The chemistry, resulting configuration, and properties of poly(3‐hexylthiophene)‐alt‐C60 copolymers prepared by either classic pyrrolidine ring formation or an atom transfer radical addition are compared. Both routes result in controlled additions of polymers to C60. Extensive macromolecular modeling through PM6 methods indicate that there is no conjugation between P3HT and C60 in the systems studied. This along with 2D‐NMR, AFM, and photovoltaic characterizations of the materials indicate the importance of the structure of the modified C60 and the nature of the linking group between C60 and P3HT segments in determining the morphology of the copolymers in the solid state. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2304–2317, 2009 相似文献
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Fullerene C60 has been covalently bound to an insoluble hydrophilic polymeric matrix: Sephadex ® G‐200. The new polymeric equivalent of C60 swells in H2O to form gel‐like suspensions. The transient photochemical behavior of this polymeric fullerene has been studied in dry and H2O‐suspended samples. Both samples show a transient absorption similar to the absorption of the parent C60 solution. There is a lack of triplet‐triplet annihilation and of a O2‐quenching process in the dry sample. On the contrary, the O2‐quenching process is very efficient in the H2O‐suspended samples (kq(O2)=(1.9±0.5)×108 dm3 mol−1 s−1) and results in the formation of singlet oxygen, which is detected by its emission at 1270 nm. These results point to this hydrophilic polymeric equivalent of C60 as a good candidate for use as a singlet‐oxygen solid sensitizer in H2O suspensions. 相似文献
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Prof. Dr. Thomas M. Klapötke Jörg Stierstorfer Prof. Dr. H. Donald Brooke Jenkins Rudi van Eldik Matthias Schmeisser 《无机化学与普通化学杂志》2011,637(10):1308-1313
This paper estimates some thermochemical (in kcal mol–1) and detonation parameters for the ionic liquid, [emim][ClO4] and its associated solid in view of its investigation as an energetic material. The thermochemical values estimated, employing CBS‐4M computational methodology and volume‐based thermodynamics (VBT) include: lattice energy, UPOT([emim][ClO4]) ≈? 123 ± 16 kcal · mol–1; enthalpy of formation of the gaseous cation, ΔfH°([emim]+, g) = 144.2 kcal · mol–1 and anion, ΔfH°([ClO4]–, g) = –66.1 kcal · mol–1; the enthalpy of formation of the solid salt, ΔfH°([emim][ClO4],s) ≈? –55 ± 16 kcal · mol–1 and for the associated ionic liquid, ΔfHo([emim][ClO4],l) = –52 ± 16 kcal · mol–1 as well as the corresponding Gibbs energy terms: ΔfG°([emim][ClO4],s) ≈? +29 ± 16 kcal · mol–1 and ΔfGo([emim][ClO4],l) = +24 ± 16 kcal · mol–1 and the associated standard absolute entropies, of the solid [emim][ClO4], S°298([emim][ClO4],s) = 83 ± 4 cal · K–1 · mol–1. The following combustion and detonation parameters are assigned to [emim][ClO4] in its (ionic) liquid form: specific impulse (Isp) = 228 s (monopropellant), detonation velocity (VoD) = 5466 m · s–1, detonation pressure (pC–J) = 99 kbar, explosion temperature (Tex) = 2842 K. 相似文献
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Dr. Helena Isla Dr. Emilio M. Pérez Prof. Dr. Nazario Martín 《Angewandte Chemie (International ed. in English)》2014,53(22):5629-5633
Supramolecular polymers based on dispersion forces typically show lower molecular weights (MW) than those based on hydrogen bonding or metal–ligand coordination. We present the synthesis and self‐assembling properties of a monomer featuring two complementary units, a C60 derivative and an exTTF‐based macrocycle, that interact mainly through π–π, charge‐transfer, and van der Waals interactions. Thanks to the preorganization in the host part, a remarkable log Ka=5.1±0.5 in CHCl3 at room temperature is determined for the host–guest couple. In accordance with the large binding constant, the monomer self‐assembles in the gas phase, in solution, and in the solid state to form linear supramolecular polymers with a very high degree of polymerization. A MW above 150 kDa has been found experimentally in solution, while in the solid state the monomer forms extraordinarily long, straight, and uniform fibers with lengths reaching several microns. 相似文献
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Uwe Ruschewitz 《无机化学与普通化学杂志》2006,632(5):705-719
The first alkali metal transition metal acetylides of general composition A2M0C2 (A = Na ? Cs, M0 = Pd, Pt) were obtained by solid state reactions of alkali metal acetylides with palladium and platinum. They are characterized by chains, which are separated by alkali metal ions. Analogous chains also separated by alkali metal ions are the characteristic structural feature of acetylides of composition AMIC2, which are accessible by reacting AC2H with MII in liquid ammonia (A = Li ? Cs, MI = Cu, Ag, Au). Despite their structural similarities they possess different properties, as acetylides of composition A2M0C2 are semiconductors with very small indirect band gaps and slightly extended C–C distances compared to a C–C triple bond, whereas acetylides of composition AMIC2 show a typical salt‐like behavior with C–C distances close to the expected value for a C–C triple bond of 120 pm. But with the help of simple chemical models these differences can be made plausible. Furthermore, it is shown that only by a combination of different methods (powder diffraction with X‐rays and neutrons, solid state NMR spectroscopy, Raman spectroscopy) it was possible to characterize this new class of compounds structurally and chemically. 相似文献
19.
The effects of ammonium sulfate aerosols on the kinetics of the hydroxyl radical reactions with C1–C6 aliphatic alcohols have been investigated using the relative rate technique. P‐xylene was used as a reference compound for the C2–C6 aliphatic alcohols study, and ethanol was used as a reference compound for the methanol study. Two different aerosol concentrations that are typical of polluted urban conditions were tested. The total surface areas of aerosols were 1400 μm2 cm?3 (condition I) and 3400 μm2 cm?3 (condition II). Results indicate that ammonium sulfate aerosols promote the ethanol/OH radical and 1‐propanol/OH radical reactions as compared to the p‐xylene/OH radical reaction. The relative rate of the ethanol/·OH reaction versus the p‐xylene/·OH reaction increased from 0.19 ± 0.01 in the absence of aerosols to 0.24 ± 0.01 and 0.26 ± 0.02 under aerosol conditions I and II, respectively. The relative rate of the 1‐propanol/·OH reaction versus the p‐xylene/·OH reaction increased from 0.45 ± 0.03 in the absence aerosols to 0.56 ± 0.02 and 0.55 ± 0.03 under aerosol conditions I and II, respectively. However, significant changes in the relative rates of the 1‐butanol/·OH, 1‐pentanol/·OH, and 1‐hexanol/·OH reactions versus the p‐xylene/·OH reaction were not observed for either aerosol concentration. The relative rates of the methanol/·OH reaction versus the ethanol/·OH reaction were identical in the absence and presence of aerosols. These results indicate that ammonium sulfate aerosols promote the methanol/·OH reaction as much as the ethanol/·OH reaction (as compared to the p‐xylene/·OH reaction). © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 422–430, 2001 相似文献
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M. A. Kuznetsov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(2):145-153
The entropies S of C7–C11 normal alkanes over the temperature and pressure ranges 300–620 K and 0.5–60 MPa were obtained by the integration of the experimental isobars of isobaric heat capacity C p . The C p data were obtained using a flow adiabatic calorimeter with calorimetric flow rate measurements. The entropy values were determined up to critical temperatures by extrapolation from the sides of liquid S′ and gas S″ phases. The p-T-S thermodynamic surfaces of the alkanes under consideration in the liquid and gas phases were constructed. A generalized temperature dependence of S′ and S″ was determined for the homologous series over the temperature range from the triple to critical point within the framework of similarity theory. 相似文献