A. V. Noskov

An investigation of the structural and thermodynamic properties of polystyrene fullerene-containing films

Polystyrene films doped with small additives of fullerenes (w = 0–1 × 10−3) are obtained. The nonmonotonic dependence of the glass transition point on composition with a minimum at w = 1 × 10−4 is revealed by the DSC method. It is concluded that there is a plasticizing action of small amounts of filler at w < 1 × 10−4 and domination of the effect of intermolecular interactions of fullerene with polystyrene at w > 1 × 10−4. It is established by small-angle X-ray scattering that composites containing fullerenes in the amount w > 1 × 10−4 are characterized by the greatest mobility of the segments in the modified polymer chains.

Hydroxyethyl cellulose/bentonite/magnetite hybrid materials: structure, physicochemical properties, and antifungal activity

Bentonite/magnetite powder was synthesized and characterized using laser diffraction, scanning electron microscopy, X-ray diffraction, low-temperature nitrogen adsorption–desorption technique, and magnetization measurements, revealing it to be a ferromagnetic material with mesopores. Hydroxyethyl cellulose was filled with bentonite/magnetite particles by mechanical dispersion to produce hybrid film materials that were studied using various methods. X-ray diffraction analysis showed that the interlayer distance in the clay was increased due to intercalation of polymer molecules. A concentration effect of the filling agent on the tensile properties of the hybrid material was revealed. Infrared (IR) spectrometry indicated an increase in the density of the hydrogen-bonding network. Microbiological tests showed that the HEC/bentonite/magnetite films exhibited antifungal effect against Candida albicans.

Sorption of heavy metal ions by fullerene and polystyrene/fullerene film compositions

The kinetics and equilibrium of the process of sorption of heavy metals from aqueous electrolyte solutions by polystyrene, fullerene, and polystyrene/fullerene composites have been studied. The kinetics of sorption of copper, nickel, zinc, and cadmium ions by the studied sorbents is described by the pseudo-firstand pseudo-second-order kinetic models. The rate constants of the process of sorption are determined. It is established that the equilibrium isotherm of sorption of copper ions by fullerene is related to the Langmuirtype isotherms. The sorption capacity of a monomolecular layer with reference to the Cu(II) ions is determined as equal to 14.6 mmol/g. Based on the calculated Henry constants, it is shown that the sorption efficiency increases in the series polystyrene < composition < fullerene.

Sorption of heavy metal ions by cellulose modified with fullerene

Celulose was modified by impregnation of the polymer with a solution of C60 nanocarbon particles in ortho-xylene. Specific features of the sorption kinetics of Cu(II),Ni(II), and Cd(II) ions on cellulose and composite materials were researched. Pseudo-first- and pseudo-second-order kinetic models were used to determine the quantitative characteristics of the process. It was demonstrated that the sorption efficiency of metal ions on fullerene-containing cellulose substantially increases. The improvement of the sorption properties of the modified polymer is due to the increase in the concentration of active sorption properties and to a change in the structure of the sorbent.

Hydrodynamic and bulk properties of dextrans in liquid media

Bulk and viscous properties of solutions of dextrans of different molecular weights in formamide, water, and dimethyl sulfoxide were studied. The fractal dimension of the biopolymer was estimated from the hydrodynamic data.

The effect of silicon dioxide concentration on thermodynamic properties of polystyrene-based composites

Sol-gel synthesis of a silicon dioxide powder is carried out. The samples of polystyrene/silicon dioxide film composites with different concentrations of the filling agent are obtained. Studies using differential scanning calorimetry show that the dependence of the glass transition temperature of the composite on the composition is nonmonotonic with a minimum at 1 wt % SiO2. It is concluded that there is a plasticizing action of small (less than 1 wt %) amounts of silica and a predominant effect of intermolecular interactions of the filling agent with the polymer at high SiO2 concentrations (more than 1 wt %) are concluded.

Effect of Polystyrene/Fullerene Composites on Free-Radical Processes in Biologic Fluid

Polystyrene films and polystyrene films filled with fullerenes were fabricated by the solution cast method. The effect of fullerene-containing polystyrene nanocomposites on free-radical processes in blood serum has been researched in vitro. The parameters of lipid peroxidation in native serum after adding nanocomposites were determined by chemiluminescent analysis and spectrophotometry. It was revealed that polystyrene/fullerene composites can manifest antioxidant properties in blood serum.

Role of mass transfer in electrochemical crystallization of copper from water-isopropyl alcohol solutions of copper sulfate

Effect of hydrodynamic conditions on the electrodeposition of copper from water-isopropyl alcohol solutions of CuSO4 was studied. The experimental data obtained were analyzed in terms of the diffusion kinetics equation for a rotating disk electrode. Electron microscopy and X-ray diffraction analysis were used to examine the chemical and granulometric composition of copper-containing electrolytic powders.

Anodic dissolution of a metal accompanied by the formation of unstable anionic complexes

Transport processes that take place during the anodic dissolution of a metal accompanied by the formation of negatively charged intermediate particles are theoretically considered. Distributions of the component concentrations and electric potential in the diffusion layer during the quasi-equilibrium decomposition of intermediate particles are calculated. Analysis predicts the existence of the admissible concentration limit of anions depending on the stability constant of intermediate particles. The effect of the stability constant on the potential distribution within the diffusion layer and on the shape of voltammetric curves of the process is found to be complex.

Diffusion kinetics of a metal anodic dissolution with forming unstable charged products

Anodic dissolution of bivalent metal in binary electrolyte, through positively charged intermediates, is theoretically analyzed. The components’ concentrations and the electrical potential distributions in diffusion layer under the intermediate quasireversible decomposition are calculated. It is shown that the electrochemical process rate decreases when the products’ stability constant increases.