N. P. Krut’ko

Modification of oxidized bitumen with styrene-butadiene-styrene copolymers of various structures

Mechanical and structural-rheological properties of oxidized bitumen modified with styrene butadiene-styrene copolymers side vinyl groups in their butadiene fragment were studied. A comparative analysis of the modified and unmodified bitumen composites was performed.

Successive adsorption of polyacrylamide compounds from electrolyte solutions on the surface of kaolinitic clay particles

Successive adsorption of oppositely charged polyelectrolytes, namely, cationic and anionic acrylamide copolymers, on a solid phase surface from solutions with high ionic strength is investigated. The constants of the Freundlich equation are calculated for the adsorption of different polymers. The interrelation between the adsorption values of polymers and their flocculation activity with respect to clay-salt suspensions is determined. The successive adsorption of oppositely charged polyelectrolytes strongly affects the flocculation due to the formation of polyelectrolyte complexes on the surface of clay particles. The mechanism for complexation is proposed.

Thermal oxidation resistance of bitumen modified with styrene-butadiene-styrene and ethylene-vinyl acetate copolymers

The effect of a blend of styrene-butadiene-styrene and ethylene-vinyl acetate copolymers on the heat resistance of oxidized bitumen was examined. The structural and rheological properties of the modified bitumen were analyzed.

Synthesis of potassium sulfate by conversion of potassium chloride and magnesium sulfate

Possibility was studied of obtaining potassium sulfate by double-stage conversion of potassium chloride and magnesium sulfate, with schoenite formed in the first stage and then decomposed with water into potassium sulfate.

Effect of binder reagents of varied nature on the strength of potassium chloride grains

Specific features of structure formation in dispersed salt systems based on potassium chloride were studied from the standpoint of a relationship between the physicochemical properties of binder reagents, granulation conditions, and grain strength.

Peculiarities of the formation of polyacrylamide compound-based polyelectrolyte complexes in the course of the flocculation of clay-salt dispersions

Peculiarities of the formation of polyelectrolyte complexes based on cationic and anionic copolymers of acrylamide having different macromolecule charge densities on the surfaces of kaolin particles in highly concentrated salt solution are investigated. The interactions of the copolymers with the clay particle surface and with each other are studied by electrokinetic and IR spectroscopy methods. The rheological properties of kaolin suspensions are investigated in a salt solution in the presence of the polyelectrolytes. The flocculation ability of the polyelectrolytes and their binary mixtures with respect to clay-salt dispersion is estimated. The mechanism for the formation of polyelectrolyte complexes on the surface of clay particles is discussed. It is shown that the complexation of oppositely charged polyelectrolytes on the surfaces of clay particles intensifies the flocculation of clay-salt dispersions.

Effect of deposition conditions on properties of nanostructured magnesium hydroxide powders

Change in the dispersity, microstructure, and adsorption properties of mesoporous magnesium hydroxide powders synthesized by the precipitation method from solutions upon introduction of surfactants and under the action of microwave and ultrasonic irradiation was studied. Highly dispersed nanostructured Mg(OH)2 powders were obtained with average sizes of primary and secondary particles of, respectively, 13–27 and 180–383 nm. The specific surface area, pore volume, and average pore diameter of the samples under study varied, depending on the preparation conditions, within the ranges 86–98 m2 g–1, 0.491–0.737 cm3 g–1, and 24–32 nm, respectively. It was shown that highly dispersed mesoporous magnesium hydroxide powders can be directionally synthesized by the precipitation method, which opens up wide opportunities for their application as nanoreactors for synthesis of nanosize isolated particles and development of poly-path catalysts on their basis.

Phase separation of salt dispersions of clay with polyacrylamide flocculants

Effect of polyacrylamide (co)polymers on the properties and structure of floccules formed in the course of phase separation of a salt dispersion of clay was studied. It was shown that, with a binary system of unlike-charged copolymers, a sediment with high density and water-yielding capacity is formed, which is necessary for the effective phase separation. The subsequent squeezing of the flocculated sediment to remove water leads to a local increase in the concentration of polymers in the solid phase, which raises the plastic strength of the sediment and improves the granulation conditions.

Topochemistry regularities in evaluation technique of phosphate raw material reactivity

Experimental approaches for evaluation of reactivity of phosphate raw material and obtaining additional information on its phase composition were suggested in view of physicochemical patterns of the phosphate raw material decomposition in a weakly acidic environment.

Synthesis of aliphatic polyamides in the dispersion medium of oxidized asphalt

The possibility of modifying oxidized asphalt by performing polycondensation of maleic anhydride with aliphatic amines of various chemical structures in the dispersion medium was considered. The influence of the reactant structures and reaction conditions on the physicomechanical and structural-rheological properties of the polymer-modified asphalt was examined.