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...     

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.     

Thermostimulated currents in low-density polyethylene and its blends with various components after high-pressure plastic deformation

It is established that the plastic deformation of low-density polyethylene (LDPE) under a pressure 0.5–2.0 GPa on a high-pressure apparatus of the Bridgman anvil type leads to the appearance of thermostimulated currents in samples, indicating that the samples contain trapped electrons. It is shown that two peaks are present on the temperature dependences of the currents; one of these is most probably related to the cold crystallization of the polymer, its structure being destroyed upon high-pressure deformation, while the other is related to the melting of the polymer. It is noted that the peaks were absent on temperature dependences of the currents for LDPE blends with some components; this could be due to the formation of a conducting state at interfaces. It is found that the electroconductivity of some blends after processing under pressure was higher than that in LDPE itself by a factor of 25.     

Solid-state synthesis of amphiphilic chitosan-polyethylene systems by the maleinization of both components

N-acylated chitosan modified by maleic anhydride was prepared by the method of the solid-state synthesis (Bridgman anvils, semipilot extruder). In contrast to the synthesis under homogeneous conditions, solid-state acylation is accompanied by the reaction of imidization of the formed amic acid as well as by reaction through double bonds, thus leading to the formation of derivatives of succinic anhydride. By simultaneous or subsequent interaction of chitosan modified with maleic anhydride with a PE matrix, either modified or not modified with maleic anhydride, new chitosan-polyethylene composite materials are prepared, and these composites are characterized by the combined valuable medicinal and biochemical properties of chitosan and high mechanical characteristics of the polyolefin component. The above composites are of obvious interest as amphiphilic sorbents, which are highly resistant to the action of aggressive media, as well as antimicrobial and biodegradable PE-based materials.     

Reaction of 3,6-di-tert-butyl-ortho-benzoquinone with zinc and aluminum under high pressure and shear deformation conditions

Conclusion The action of high pressure and shear deformation permits the reaction of 3,6-di-tertbutyl-o-benzoquinone with zinc and aluminum, which cannot be carried out under ordinary conditions. A hypothesis was offered for the mechanism of the reaction under HP + SD conditions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2800–2801, December, 1986.     

Mass spectrometry of the products of the mechanochemical degradation of amylose macromolecules

The destruction of amylose at high pressures (20 MPa) combined with shear deformations (540°) was studied. The destruction products were analyzed by mass spectrometry. The degradation of the polysaccharide caused by the extremal mechanical and mechanochemical treatment of amylose macromolecules was investigated. The formation of an appreciable amount of low-molecular oligomers was explained by the predominant cleavage of chains near the boundary zones of crystallites.     

Calorimetric investigation of some polysaccharides subjected to high-pressure plastic deformation

Differential scanning calorimetry is used to establish that, at 20–200°C, an endothermic process proceeds in polysaccharides (cellulose, methyl cellulose, cellulose di- and triacetate, chitin, chitosan, starch, etc.) whose enthalpy is noticeably enhanced after plastic deformation of the polymers at 0.5–2.0 GPa. By the example of cellulose, it is shown that the process is associated with water present in the polymers. An increase in the enthalpy as a result of pressure treatment is due to both structural transformation of cellulose I into cellulose II and the intensification of intermolecular interactions in the polymers that is due to formation of a system of electric charges in the samples.