02.00.00 Chemical sciences
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Description
In the article the mathematical model of the space charge region in the bipolar membrane is considered. The structure of the space charge region under passing of electric current, and without electric current is discussed. The results of experimental studies of water dissociation in the bipolar membrane in the presence of chromium(III) are discussed
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Description
Surface energy of polymers determines such important properties of polymers like wetability, adhesion, ability adsorption of low molecular weight substances. Inner organization, the structure of the polymer and the dynamics of interaction between macromolecular chains are shown at last. At the same time, the micro-defects (inhomogeneity) of polymers, which is an integral part of the structure are changed during deformation and must contribute to changing of the surface energy and its components. This article solves the task of detecting changes in the parameters of surface energy of polymers under uniaxial deformation. Data for the quantitative indicators of the surface properties total surface energy and its dispersive and polar components are presented. The calculations showed that the disperse and polar components of all the samples of polymer materials are about 98% of the total and, therefore, is crucial. For the first time experimental data, illustrating the change of surface energy of polymeric materials had been obtained, including elastomeric compositions, when uniaxial deformation. The relative changes of the surface energy vary from 54.5 per cent to 125 %. A decrease of total surface energy and its dispersion component is observed during deformation of polymer samples of different structure and chemical nature
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Description
A number of thermoreactive oligomers was obtained via the Michael interaction of molar excesses of hexamethylene-bis-maleimide with 5,5’-bisbenzotriazoles in melt. The structure of them was proved by the 13C spectroscopy method. The one-step synthesis in melt, without by-products evolution, in absence of organic solvents, additional reagents, and catalysts is the more acceptable in point of view of technology (a finished reaction product does not require any purification). The process itself is the nucleophile addition across double bond, and so it can be attributed to the atom-saving technologies. According to data of the dynamic scanning calorimetry (DSC) and the thermogravimetry (TG), oligomers fuse at 130.8–135.6 °С, cross-link at 185–250 °С, and begin their thermal destruction in air at temperatures of 400– 420 °С. The tensile strength at shear of the glued joints on base of oligomers (steel plates overlapped) is 14.2– 23.7 MPa (142–237 kgf/cm2 ). The positive effect from the introduce of 5,5’-bis-benzotriazolyl fragments into structure of bismaleimide thermoreactive oligomers on strength of the glued joints between metal plates was revealed
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PREPARATION OF GRAPHENE MATERIAL WITH BENZIMIDAZOLE FRAGMENTS
DescriptionThe new benzimidazole-functionalized graphene material based on graphene oxide (GO) and 3,3',4,4'- tetraaminodiphenyl oxide (TADPO) was obtained under one-step hydrothermal synthesis conditions. According to IR spectroscopy and elemental analysis, as a result of the reaction, benzimidazole (BI) rings are formed, and the mass content of nitrogen is 12.3%. The new graphene material is characterized by excellent electrochemical efficiency in a threeelectrode supercapacitor. As a result of the redox activity of BI cycles the specific capacitance reaches 286 F/g at the scan rate of 2 mV/s, which is substantially higher than the reduced graphene oxide (RGO) sample obtained under similar conditions without using TADPO (159 F/g at 2 mV/s)
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Description
The present article belongs to the area of organic chemistry, namely, to chemistry of heterocyclic compounds. For the purpose of optimization of a method of synthesis the threecyclic heteroaromatic systems containing a pyridi-ne, thiophen and pyrimidine ring in one molecule, - tetrahydropyridothienopyrimidinon and dihydropyri-dothienopyrimidinon – reaction 3-aminothieno[2,3-b]-pyridine-2-carbokxamides with aromatic aldehydes is studied, some of which contain pharmacolodical groups. Reaction was carried out in the conditions of an acid catalysis – is used p-TsOH. Influence of the nature of solvent (toluene, ethanol, mix ethanol-dimethilform-amide (1:1)) on the course and the direction of reaction are studied. It is established that carrying out reaction in toluene leads to the dihydropyrimidine containing in situation 2 phenyl, 4-bromphenyl deputies. In the presence in a molecule of initial aldehyde of the deputy in orto-situation tetrahydropyrimidine are formed. Use of ethanol mainly leads to formation of a tetrahydro-pyrimidine ring. Boiling of initial substances in mix ethanol-DMF yields the results similar to use of toluene, but time of reaction is reduced twice. The way of receiving the dihydroderivatives short-term boiling of tetrahydropyrimidine is found in mix isopropanol-DMF (a volume ratio of solvents 1:3). Identity of the received substances is proved by method of a thin layer chroma-tography. The structure of the synthesized connections is confirmed with the element analysis. The structure of tertagidropirimidinon and digidropirimidinon is proved with use of data of IK and NMR 1H of the spectral analysis
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Description
This publication examines the relationship between the structure of molecules of complexing (descriptors of electronic structure), which are used as inhibitors of hydrogen embrittlement of the steel grade St3, and the content of absorbed hydrogen in model samples-plates made of the above steel. The form of expression of this relationship is the correlation coefficient (CC) by Pearson
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Description
The current-voltage characteristics and the number of effective ion transfer, as well as the frequency spectrum of the electrochemical impedance of multilayer ion-exchange membranes in a stable and controllable thickness of the diffusion layer were measured, using the of rotating membrane disk complex. The article presents a comparative analysis of the frequency spectra of the electrochemical impedance of the source and a surface-modified monopolar anion exchange membranes in 0.01 M sodium chloride was made. The process of water molecules dissociation at current densities above the limiting one in 0.01 M sodium chloride solution was studied in detail
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SYNTHESIS OF SUBSTITUTED PYRIDINE- 3-SULFONYL ISOCYANATES AND PYRIDINE- 3-SULFONYL UREAS
DescriptionAcylation of amides substituted with pyridine-3- sulfonic acids oxalil-chlorides and phosgene was studied. New pyridil-3-sulfonil isocyanates were synthesized. The conditions for this synthesis were optimized by taking into account the detailed understanding of this acylation. The synthesized pyridine-3-sulfonyl isozyanates were converted to pyridine-3-sulfonyl ureas. Biological activity of the new compounds was studied and the substances with high herbicidal effect were found
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KEPLER'S NUMBERS IN THE MODEL OF THE RUTHERFORD-BOHR
DescriptionThe change in the Kepler’s atomic number in the Periodic Table of Mendeleev is studied. It is shown that its values decrease regularly with increasing nuclear charge. An alternative formula for computing the values of the Kepler’s atomic number is proposed. It is shown that the ratio of the atomic number of Kepler’s to the mass of the atom is a constant for each period. The values of these constants are calculated
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Description
Macrodeficiency of polymeric materials, including the pervasive one, is a consequence of the development of initial microdefects which appear in polymers both due to external factors and during their processing. In the article, the problem of the detection of structural microdeficiency of various polymeric materials through an assessment of their structural parameters is solved. The considered materials possess approximately identical degree of crystallinity (60 – 66%), but different density. The express assessment technique of polymeric materials microdeficiency by the sorption method with the use of the academician M. M. Dubinin’s theory of volumetric micropore filling is developed and evaluated. On the basis of a quantitative assessment of sorption processes in polymeric materials, including elastomeric compositions – rubbers and rubberized fabrics, the existence of the initial local microdefects arising in the course of synthesis is established. In real polymeric materials, including elastomeric compositions – rubbers and rubberized fabrics, the existence of the initial local microdefects arising in the course of synthesis is established (the number of microdefects n varies from 1x1017 sm-3 to 6x1019 sm-3 , and the rated linear size k – from 2 nm to 7 nm). The general reduction of microdeficiency in rubberized fabrics in comparison with initial rubber is revealed and rationalized