Complexation of anion exchangers based on polyimines and allyl and epoxy compounds with transition metal cations

Complexation of polymeric anion exchangers with transition metals was studied by polarographic and potentiometric titration techniques.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 10, 2004, pp. 1693–1698.Original Russian Text Copyright © 2004 by Ergozhin, Chalov, Kovrigina, Iskakova, Nikitina.     

Strong and weak relaxation polarization in dielectric statistical mixtures of non-extended particles

The heterogeneous dielectric in the form of a statistical mixture of nonextended particles is considered; the existence of through conductivity in each component is examined, and an expression for the complex dielectric permeability of this system is obtained. The conditions for the development of strong relaxation polarization in such systems are found. The transition from strong to weak relaxation polarization is identified from an increase in the relationship between the contributions of the relaxation polarization and the fast polarization processes to the effective polarizability of a heterogeneous system and a change in the distribution parameter.     

Polyfunctional Anion Exchangers Based on Copolymers of Allyl Glycidyl Ether and Polyamines

Polyfunctional anion exchangers were prepared by copolymerization of allyl glycidyl ether with polyamines in the presence of a promoter. The synthesis conditions were optimized. The composition and physicochemical features of the resins prepared were studied.     

Determining the form of a relaxator distribution by extrapolation

А new way of determining types of relaxator distribution and their parameters is proposed. It is based on calculating the slopes of high-frequency and low-frequency asymptotes in the frequency dependences of the real and imaginary parts of complex dielectric permittivity and conductivity in dielectrics with polarization relaxation.     

Strong relaxation polarization in a double-layer capacitor

In dielectrics, strong relaxation polarizations develop that contribute much to the polarization of the substance. Such great contributions should be expected in heterogeneous dielectrics. Relaxation polarization is studied in the simplest of heterogeneous dielectrics: a double-layer capacitor. The areas of concentration of the development of strong relaxation polarizations, the locations of which depend on the ratios of permittivities and the through electrical conductivities of the layers, are determined. The transition to strong relaxation polarization in this case also occurs in accordance with criteria developed earlier.     

Performance of anion exchangers based on aniline,epichlorohydrin, and polyamines in sorption of molybdenum(VI) ions

Polyfunctional anion exchangers based on aniline, epichlorohydrin, and some polyamines were synthesized. The composition and structure of the anion exchangers were studied by IR spectroscopy and elemental analysis. Molybdenum sorption was studied by classical polarography, and dependences of the sorption of molybdenum(VI) ions on the solution acidity, concentration of metal ions, and time of contact of the resins with the Na₂MoO₄ solution were determined in batch experiments. These ion exchangers exhibit high performance in sorption of molybdenum ions. The developed sorbents with increased sorption ability can successfully solve problems of removing molybdenum(VI) ions from process effluents in nonferrous metallurgy.     

Kinetics of polycondensation of allyl bromide and monoethanolamine vinyl ether with resorcinol diglycidyl ether

Polycondensation of resorcinol diglycidyl ether, monoethanolamine vinyl ether, and allyl bromide in dimethylformamide solution was studied. The kinetic parameters of the process were determined.

     

Determining the relaxation polarization parameters in dielectrics with high electrical conductivity

In dielectrics with high steady leakage of conductivity, the frequency–temperature dependences of the dielectric loss tangent generally allow us to determine the relaxation time and activation energy of relaxation process only when they are strong. With weak relaxation processes, there are no extrema in the frequency dependence of the dielectric loss tangent. In such cases, the parameters of the relaxation processes are initially determined from the frequency behavior of the imaginary parts of the electrical module or impedance. However, the frequency dependences of these quantities when there is electrical conduction can contain three extrema. Identifying the maxima associated with relaxation polarization therefore requires additional research.     

Ion-Exchange Polymers Based on Dihydroxydiphenylpropane Diglycidyl Ether,Allyl Halides,and Amines

Polycondensation of dihydroxydiphenylpropane diglycidyl ether and allyl halides in the presence of some polyamines was studied. The optimal conditions of formation of ion-exchange polymers with three-dimensional structure, their composition and structure, and also physicochemical characteristics were determined.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 1, 2005, pp. 146–150.Original Russian Text Copyright © 2005 by Ergozhin, Chalov, Kovrigina, Iskakova.     

Fluorescence of Supported Phospholipid Bilayers Recorded in a Conventional Horizontal-Beam Spectrofluorometer

Supported phospholipid bilayers are a convenient model of cellular membranes in studies of membrane biophysics and protein-lipid interactions. Traditionally, supported lipid bilayers are formed on a flat surface of a glass slide to be observed through fluorescence microscopes. This paper describes a method to enable fluorescence detection from the supported lipid bilayers using standard horizontal-beam spectrofluorometers instead of the microscopes. In the proposed approach, the supported lipid bilayers are formed on the inner optical surfaces of the standard fluorescence microcell. To enable observation of the bilayer absorbed on the cell wall, the microcell is placed in a standard fluorometer cell holder and specifically oriented to expose the inner cell walls to both excitation and emission channels with a help of the custom cell adaptor. The signal intensity from supported bilayers doped with 1 % (mol) of rhodamine-labeled lipid in the standard 3-mm optical microcell was equivalent to fluorescence of the 70–80 nM reference solution of rhodamine recorded in a commercial microcell adaptor. Because no modifications to the instruments are required in this method, a variety of steady-state and time-domain fluorescence measurements of the supported phospholipid bilayers may be performed with the spectral resolution using standard horizontal-beam spectrofluorometers.