Rheological characteristics and relaxation properties of polymer-nanodiamond composites

The effect of modifying additives of nanodispersed substances on rheological and relaxation properties of composite materials based on polydimethylsiloxane was examined. The effect of modifying additives on relaxation properties of polymeric composite materials was considered within the framework of elastic strain theory using the Mooney-Rivlin model.     

Structure,mechanical, and tribological characteristics of polyurethane modified with nanodiamonds

The effect of modifying additives based on detonation nanodiamonds on the tribological characteristics of polyurethane rubber is studied. Introduction of modifying additives based on detonation nanodiamonds (0.5 wt %) leads to a marked improvement in the antifriction and wear-resistance characteristics under conditions of boundary sliding friction for steel and for lubrication with water. The attained tribological characteristics (total energy loss for friction, weight loss of polymer during tribological contact, maximum admissible working pressure) are well (∼300%) above the corresponding characteristics of foreign analogs. Changes in the tribological characteristics of the formed nanocomposite material are observed, but the elastic and strength characteristics remain unchanged.     

Environmental problems of wood biomass processing. Waste processing lignin

in this paper the ecological problems of wood biomass processing are analyzed. The strongest attention is drawn to the problem of recycling and processing waste materials containing lignin with the help of high temperature self-propagating synthesis.     

Perspectives for thiamin as a preparation for correction of free radical states of different origin

Аntioxidant capacity of thiamin has been investigated, Liposome suspension being the standard biological test-system has been used for this purpose Antioxidant capacity of thiamin has been investigated. Liposome suspension being the standard biological test-system has been used for this purpose. Thiamin usually being not included in the list of antioxidant substances is able to interfere the processes of lipid peroxidation. Such effects give the possibility to extend the scale of thiamine practical application and to recommend it for correction different free radical states including environmentally induced free radical diseases.     

Surface modification of detonation nanodiamonds by the perfluorobutyl radical

The method was developed for surface defunctionalization of detonation nanodiamonds by substitution of a perfluorinated organic radical for hydroxyl and carboxyl groups. Size-mass distributions of modified particles of detonation nanodiamonds in water and toluene were studied     

Prospects for Development of an Eco-Friendly Nanocarbon Matrix for Combined Immobilized Microbial Preparations

A new method for graphene preparation by self-propagating high-temperature synthesis process was proposed. The effect of the resulting material on various microorganisms and the process of graphene nanoparticles conjugation with microbial cells were discussed.

     

Structure of the dispersive medium and sedimentation resistance of suspensions of detonation nanodiamonds

The specific features of the stabilization of suspensions formed by detonation nanodiamonds in polar and nonpolar media are investigated. It is demonstrated that the polydispersity of nanodiamond particles in an aqueous medium periodically changes in an ultrasonic field. The conditions are determined under which the optimum dispersity can be maintained for a long time. A technique is devised for chemical modification of the nanodiamond surface through the grafting of organosilyl groups. This technique makes it possible to prepare finely dispersed suspensions of nanodiamonds in nonpolar organic media. A model is proposed for an aggregate that consists of detonation nanodiamond particles and is stabilized through hydrogen bonds formed by functional groups of different types.     

Self-organization in nanocomposites based on detonation nanodiamonds

Physics of the Solid State - The effect of modifying detonation nanodiamond additives on the stress-strain properties of polymer nanocomposites is investigated using polysiloxane polyblock...     

Environmental problems of finely dispersed titanium dioxide production

Finely dispersed titanium dioxide is widely used in modern technologies. Proved reserves of titanium ores in Russia are expected to meet industrial needs. However, the available facilities for the manufacture of titanium dioxide from ores are clearly insufficient, which naturally requires new plants to be put into operation. The technologies used for the production of titanium dioxide were developed as early as 1940s, when ecological aspects of the production process were almost not taken into account. The present survey analyzes environmental problems related to the titanium dioxide production according to the sulfate and chloride technologies in comparison with the fluoride process proposed for industrial implementation. The fluoride process has been examined as applied to ilmenite from the Turan deposit in Tomsk oblast, and some actions directed toward improvement of ecological parameters of this process have been proposed.     

The thermodynamics of dissolution of low-molecular-mass compounds in polymethyl[2′-(3-trifluoromethyl-2,2,3-trifluorocyclobutyl)ethyl]siloxane studied via inverse gas chromatography

The effect of the 2′-(3-trifluoromethyl-2,2,3-trifluorocyclobutyl)ethyl radical in fluorosiloxane on the thermodynamics of dissolution of various low-molecular-mass compounds in this polymer is studied via inverse gas chromatography. The activity coefficients at infinite dilution, Ω ₁ ^∞ , in the temperature range 20–100°C are determined for C₆–C₈ n-alkanes, cyclohexane, benzene, toluene, tetrachloromethane, trichloromethane, 2-butanone, and ethyl acetate. Flory-Huggins interaction parameters χ ₁₂ ^∞ are calculated. It is shown that hydrocarbons are poor solvents (Ω ₁ ^∞ > 6, χ ₁₂ ^∞ > 0.5) and that the studied fluorosiloxane is not inferior to commercial polymethyl(3,3,3-trifluoropropyl)siloxane with respect to stability in nonpolar liquid media in the range 20–70°C. Trichloromethane (above 50°C) and compounds containing a carbonyl group are found to be good solvents. The dispersion component of the solubility of the polymer, δ ₂, is determined to be 14.0 (J/cm³)^1/2 at 20°C and slightly lower, 13.5 (J/cm³)^1/2, at 100°C. Possible causes of these low values of δ₂ are discussed.