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101.
Shin‐Ichi Yamamoto Joanna Pietrasik Krzysztof Matyjaszewski 《Journal of polymer science. Part A, Polymer chemistry》2008,46(1):194-202
Statistical copolymers of di(ethylene glycol) methyl ether methacrylate (MEO2MA) and tri(ethylene glycol) methyl ether methacrylate (MEO3MA) were synthesized by atom transfer radical polymerization (ATRP) providing copolymers with controlled composition and molecular weights ranging from Mn = 8,300–56,500 with polydispersity indexes (Mw/Mn) between 1.19 and 1.28. The lower critical solution temperature (LCST) of the copolymers increased with the mole fraction of MEO3MA in the copolymer over the range from 26 to 52 °C. The average hydrodynamic diameter, measured by dynamic light scattering, varied with temperature above the LCST. These two monomers were also block copolymerized by ATRP to form polymers with molecular weight of Mn = 30,000 and Mw/Mn from 1.12 to 1.21. The LCST of the block copolymers shifted toward the LCST of the major segment, as compared to the value measured for the statistical copolymers at the same composition. As temperature increased, micelles, consisting of aggregated PMEO2MA cores and PMEO3MA shell, were formed. The micelles aggregated upon further heating to precipitate as larger particles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 194–202, 2008 相似文献
102.
103.
Joanna Kobyłecka Bogdan Ptaszyński Anna Zwolinńska 《Monatshefte für Chemie / Chemical Monthly》2000,131(1):1-11
Summary. Sparingly water soluble complexes of lead(II), cadmium(II), and zinc(II) with N-phosphonomethylglycine (glyphosate, NPMG) of the general formulae C3H6O5NPPb, C3H6O5NPCdċ2H2O, and C3H6O5NPZn were synthesized. The complexes were also precipited from a dilute Roundup solution, and their solubility in water was
determined. Thermal, diffractometric, and IR spectrophotometric analyses were carried out. It was found that the metal is
bonded to glyphosate through the oxygen atoms of the carboxylic and phosphonate groups; metal-nitrogen binding is absent in
the above compounds. Studying the complexing behaviour in solution by UV spectrophotometry pointed out that a complex of the
composition Pb(II) : NPMG=1:1 with an absorption band at 232 nm is formed. Its stability constant as determined by Job’s method is logK=5.9±0.1. Using potentiometric techniques, the dissociation constant of N-phosphonomethylglycine and the stability constants
of its complexes with cadmium (II) and zinc (II) were determined.
Received June 30, 1999/Accepted July 21, 1999. 相似文献
104.
We show that for each p∈(0,1] there exists a separable p -Banach space Gp of almost universal disposition, that is, having the following extension property: for each ε>0 and each isometric embedding g:X→Y, where Y is a finite-dimensional p-Banach space and X is a subspace of Gp, there is an ε -isometry f:Y→Gp such that x=f(g(x)) for all x∈X. 相似文献
105.
106.
Anna Chachaj-Brekiesz Krzysztof Zborowski Joanna Zemła Katarzyna Makyła-Juzak 《Molecular physics》2013,111(24):3567-3577
Symmetrical triblock semifluorinated n-alkane, di(perfluorohexyl)hexane of the formula F(CF2)6(CH2)6(CF2)6F (abbreviated F6H6F6), has been synthesised and investigated at the air/water interface. Our results show for the first time that this unusual film-forming material, completely hydrophobic in nature and possessing no polar group, is capable of stable film formation at the free water surface. The surface pressure–area isotherm of the studied compound exhibited two regions: corresponding to monotonous pressure rise, followed by a pseudo-plateau region. Visualisation of film structure with Brewster angle microscope (BAM) proved the formation of domains within the pseudo-plateau region. A closer insight into the structure of these domains with atomic force microscope (AFM) proved their ordered, circular shape. The average area of F6H6F6 domain was found to depend on surface pressure value, as it is 4.98 ± 1.75 μm2 at π = 1.2 mN/m to 16.54 ± 0.31 μm2 at π = 1.7 mN/m. Following performed quantum-chemical calculations, it can be concluded that the observed surface aggregates from F6H6F6 are formed by linear conformers with shifted CF and CH parts. The calculated domain thickness is between 20 and 21 Å, which perfectly agrees with the experimental value estimated from AFM measurements (20.3 ± 1.4 Å). 相似文献
107.
This article describes liquid crystalline properties of the homologous series of 4-decyloxybenzylidene-4′-alkyloxyanilines. Based on the polarization microscopy (POM and TOA methods) and the calorimetric (DSC) measurements a rich polymorphism has been detected. Investigated compounds exhibit nematic, smectic A, smectic C, smectic B, smectic I and G (smectic G) mesophases with their characteristic configurations. The presence of these mesophases was confirmed by the miscibility method, using 4-heptyloxybenxylidene-4′-pentylaniline as a mesophase reference. Nine other smectic standards with different polarity have been applied in order to investigate their influence on the mesophase stability. 相似文献
108.
D. Skrzypek B. Szymanska Joanna Wiecek Mavroudis A. Demertzis 《Journal of Physics and Chemistry of Solids》2006,67(12):2550-2558
The interaction of iron (III) with pipemidic acid, Hpipem, afforded the complex [Fe (pipem) (HO)2 (H2O)]2. The new complex has been characterised by elemental analyses, infra-red, EPR and XPS spectroscopies. The monoanion, pipem, exhibits O, O ligation through the carbonyl and carboxylato oxygen atoms. Six coordinate dimer distorted octahedral configuration has been proposed for [Fe (pipem) (HO)2 (H2O)]2. 相似文献
109.
Anna Krebs Barbara Starczewska Helena Puzanowska-Tarasiewicz Joanna Sledz 《Analytical sciences》2006,22(6):829-833
Three simple spectrophotometric methods have been described for the assay of olanzapine in its pure and pharmaceutical formulations. The direct method (A) is based on the drug oxidation with excess of N-bromosuccinimide in acidic medium and the two indirect methods (B and C) are based on the oxidation of the drug with excess of N-bromosuccinimide and cerium(IV)sulfate, followed by the reaction of the unconsumed oxidants with celestine blue. The calibration graphs were linear over the range 10 - 120 microg mL(-1) (method A), 0.5 - 6.0 microg mL(-1) (method B) and 0.6 - 3.0 microg mL(-1) (method C). After validation, the proposed methods were successfully applied to assay of olanzapine in its commercial tablets with mean percentage recoveries of 101.23 +/- 0.10, 96 +/- 0.10 and 94 +/- 0.04%. The mechanism of olanzapine oxidation with N-bromosuccinimide was also proposed. 相似文献
110.