N. A. Bagrovskaya

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.

Sorption properties of fullerene-modified polystyrene

Polystyrene is modified with fullerene, and composite films are obtained. The kinetics of sorption of heavy metal ions from aqueous electrolyte solutions on the initial and modified polystyrene films is studied. The efficiency of sorption of copper ions of the modified polymer is found to be four times higher than on the unmodified samples. The selectivity of sorption on the composite can be presented with the following order: Cu(II) ≥ Cd(II) > Ni(II) > Zn(II). The interaction between polystyrene and fullerene is studied by IR spectroscopy.

Sorption properties of cellulose-containing material modified in plasma–solution system

The treatment of a natural cellulose-containing material with an electrolyte solution activated with a glow-discharge plasma at atmospheric pressure is carried out. The sorption-kinetic characteristics of modified sawdust with respect to zinc ions are obtained. It is found that the kinetics of sorption is adequately described by the pseudofirst-order rate equation of the cation for reversible processes. The limiting stage of the sorption process is the intradiffusion kinetics. It is determined that the efficiency of sorption of zinc ions on a modified sorbent increases approximately twofold with an almost 30-fold reduction in the sorption time in comparison with the similar characteristics of unmodified samples. IR spectroscopy revealed structural and chemical changes in the modified material.

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.

Synthesis, structure, and properties of a bentonite–magnetite composite

A bentonite–magnetite composite is obtained by means of bentonite intercalation with iron oxide Fe3O4. Using the methods of electron microscopy, low-temperature nitrogen vapor adsorption–desorption, and XRD phase analysis, the composite morphology, structure, and texture have been investigated. It is shown that the synthesized bentonite–magnetite composite can be used as a sorbent for wastewater purification from organic pollutants.

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.

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.

Synthesis of copper-bearing powders and obtaining composite metallopolymeric materials

The electrochemical method was used to synthesize the nanoscale powders of copper and its compounds from the aqueous isopropanol solutions. The immobilization of nanoscale powders of copper in a polymer matrix of hydroxyehtylcellulose (HOEC) was performed using the method of mechanical dispersion. The character of the distribution of copper-bearing particles in the polymer matrix was studied. The methods of X-ray structural analysis and IR spectroscopy were used to examine the structure of nanocomposites and determine the character of interaction of copper-bearing nanoscale particles with hydroxyehtylcellulose.

Sorption properties of plasma-modified flax fibers

Effect of plasma modification on the sorption properties of short flax fibers for Zn(II) ions was studied.