Synthesis and reactivity of metal-containing monomers 72. Monomeric and polymeric metal acetylenecarboxylates and their nanocomposite products: synthesis,structures, and properties

Methods for the synthesis of a number of transition metal acetylenedicarboxylates were developed. The ways and conditions for their polymerization were studied. The polymerization of metal acetylenedicarboxylates was accompanied by the formation of polyconjugated chains. Controlled thermolysis of metal acetylenedicarboxylates yielded matrix-stabilized metal nanoparticles. The microstructures and magnetic properties of the nanocomposites obtained were examined.     

Synthesis and electrochemical properties of lithium-vanadium bronze

Original method for synthesis of a lithium-vanadium bronze was developed. The method includes mechanical activation of a mixture of metavanadic acid and lithium carbonate in the course of a plastic flow under twisting.     

Effect of plastic deformation on the character of micro-brownian motions in glassy poly(methyl methacrylate)

Glassy PMMA samples are plastically deformed at room temperature in the uniaxial compression regime to residual strains of e _res = 25%. Dielectric spectra of the initial and deformed samples are recorded via the method of broadband dielectric spectroscopy in the frequency range f = (5 × 10^?4) ? 10⁷ Hz. The results are compared with the dynamic mechanical spectra of samples deformed under the same conditions. Dielectric and mechanical spectra are noticeably distorted by deformation. As a result, dielectric permittivity ??? increases, shear modulus G?? decreases, and the intensity of dielectric ?? losses slightly increases, while dielectric and mechanical ?? losses increase appreciably. In addition, the ??anomaly?? of total dielectric ???_tot and total mechanical ??G _tot dispersions (???_tot = ?₀ ? ?_?? ?? ???_?? + ???_?? and ??G _tot = G ₀ ? G _?? ?? ??G _?? + ??G _??) occurs, that is, the polymer is transformed from the state with ???_?? ? ???_?? and ??G _?? < ??G _?? into the state with ???_?? > ???_?? and ??G _?? > ??G _??. The described phenomenon is related to a strong gain in ?? dielectric and mechanical losses in the deformed material. It is found that ?? losses increase owing to an anelastic deformation component arising during glass loading. This component is responsible for an increase in the internal energy of the glass during its anelastic deformation. Possible causes of the observed effects are discussed.     

Electrochemical Characteristics of Fluorocarbon Electrodes as a Function of the Type of Fluorinated Material

Electrochemical characteristics of fluorocarbon electrodes prepared from powdered (carbon black, coke), porous (cellular graphite), and textile (carbon cloth Ural-2T) fluorinated materials are studied. The major contribution to the electrode polarization is made by the diffusion constituent, which is different for different fluorocarbon materials. All the polarization constituents increase with the discharge current. A relative increase in the ohmic and diffusion constituents is greater than that in the electrochemical constituent.     

Thermal Processes in Aluminum Blends with Some Alcohols after High-Pressure Plastic Deformation

Binary blends of powdered aluminum with polyhydric alcohols (pentaerythritol, trimethylolpropane, neopentyl glycol, and poly(vinyl alcohol)) have been subjected to plastic deformation under pressures of 0.5–2.0 GPa. Differential scanning calorimetry has shown that exothermic processes occur in the blends due to the interaction of the organic phase with aluminum atoms on a freshly formed surface of aluminum particles.     

Effect of Silver Vanadate Additions on the Electrochemical Characteristics of the Fluorocarbon Electrode

Russian Journal of Electrochemistry - An original method for the synthesis of silver vanadate was developed. It includes mechanical activation of the precursor in the course of plastic deformation...     

Structural and Electrochemical Characteristics of Lithiated Manganese Oxides

An LiMn₂O₄ spinel of a poorly ordered structure is produced by subjecting MnO₂ + LiOH and MnO₂ + LiOH + 5 wt % Cr₂O₃ mixtures to plastic deformation at 1–2 GPa and then annealing them at 400°C. The size of individual particles is 10–100 nm. Cathodes based on chromium-modified spinels have a higher stability and a longer shelf life.     

Thermally induced processes in mixtures of aluminum with organic acids after plastic deformations under high pressure

DSC is used to measure the thermal effects of processes in mixtures of solid organic dibasic acids with powdered aluminum, subjected to plastic deformation under pressures in the range of 0.5–4.0 GPa using an anvil-type high-pressure setup. Analysis of thermograms obtained for the samples after plastic deformation suggests a correlation between the exothermal peaks observed around the temperatures of degradation of the acids and the thermally induced chemical reactions between products of acid degradation and freshly formed surfaces of aluminum particles. The release of heat in the mixtures begins at 30–40°C. The thermal effects in the mixtures of different acids change according to the order of acid reactivity in solutions. The extreme baric dependences of enthalpies of thermal effects are associated with the rearrangement of the electron subsystem of aluminum upon plastic deformation at high pressures.     

Study of the pressure distribution over rotatable bridgman anvils

Study has been made of the pressure distribution over rotatable Bridgman anvils prepared from KhVG steel and VK-6 alloy, working at room temperature and over the pressure range from 10 to 40 kbar. The pressure distribution was determined by following the polymerization of acrylamide under the combined action of high pressure and deformational shear. The polymer yield was found to increase with increasing pressure at fixed angle of rotation of the anvil. Study was made of the effect of pressure on the polymer yield over various annular zones marked out within the sample. The pressure distribution was found to vary with the material of which the anvil was constructed, the normal pressure, and the sample geometry. It was also found that there was one interval within which the pressure over the anvil was almost constant.     

Thermostimulated processes in starch-bis(hydroxymethyl)propionic acid mixtures subjected to high-pressure plastic deformation

DSC and thermogravimetry are employed to study starch, bis(hydroxymethyl)propionic acid, and their mixtures of different compositions subjected to plastic deformation under pressures of 1 and 3 GPa. An endothermic peak with an enthalpy of 300 J/g observed in the thermogram of starch is most likely related to the breakage of hydrogen bonds. Treatment under pressure greatly reduces the enthalpy of this peak. For initial mixtures, the enthalpies of the endothermic peak of starch and the endothermic peak of melting of the acid are lower than those for individual components because of chemical interaction occurring between the mixture components during heating. The high-pressure treatment makes the decrease in the enthalpy of endothermic processes much more pronounced for both components.