Magnetic resonance of the RbMnBr<Subscript>3</Subscript> antiferromagnet under pressure

The antiferromagnetic resonance spectrum was experimentally studied for a noncollinear RbMnBr₃ antiferromagnet under a mechanical pressure applied to the sample in various directions. It is shown that the incommensurate magnetic phase existing in the initial system in the presence of regular crystallographic distortions is sensitive to the pressure applied along one of the sample axes. The critical transition field to the commensurate phase decreased under pressure. It was also found that the pressure influences the uniaxial anisotropy appearing in the crystal basal plane in the presence of orthorhombic distortions. These effects were analyzed with allowance for the domain structure of the sample.     

Change in the Rheological Properties of Oil Disperse Systems upon a Vibrational Treatment

The effect of a vibrational treatment on the rheological properties of highly structured oil disperse systems is studied. A maximal decrease in the rheological parameters is observed after 20-min vibrational treatment for paraffin-rich and highly resinous oils and after 5-min treatment for mazut. The vibrational treatment is shown to be the most effective for oils with an increased content of paraffins. It is revealed that the magnetic treatment decreases the congelation temperature of oil.     

Antimicrobial activity of Ag0-nanocomposite copolymer of 1-vinyl-1,2,4-triazole with sodium acrylate

Russian Chemical Bulletin - Hydrophilic copolymer was obtained by radical copolymerization of 1-vinyl-1,2,4-triazole with sodium acrylate and used as a stabilizing matrix for metallic silver...     

Polymer nanocomposites with iron oxide nanoparticles

Novel polymer nanocomposites with iron oxide nanoparticles in a poly(1-vinyl-1,2,4-triazole) matrix are promising for the development of new biomedical materials of long-term effect.     

Synthesis and biological activity of new polymeric silver-containing nanocomposites

Russian Chemical Bulletin - The formation of new polymeric nanocomposites with silver nanoparticles incorporated into the matrix of 1-vinyl-1,2,4-triazole copolymers with vinyl acetate was studied....     

Reaction of sulfur with poly(vinyl chloride)

The reaction of elemental sulfur with poly(vinyl chloride) is studied in 1,2,4-trichlorobenzene and without any solvent under various conditions. Black polymers containing 3.77–57.64% chemically bonded sulfur and, according to IR spectroscopy, including >C=C< and >C=S groups in macromolecules are obtained. It is shown that the diffraction curves of poly(vinyl chloride) and of the reaction product containing 7.82% almost coincide but that the thermal stability of the latter is considerably higher than that of the initial polymer. The prospects of the practical use of the products of the reaction of poly(vinyl chloride) with elemental sulfur are demonstrated.     

2-Arylazo-1-vinylpyrroles: oligomerization in the presence of protic and aprotic acids

2-Arylazo-1-vinylpyrroles react with protic (CF₃COOH, HCl) and aprotic (BF₃) acids forming deeply colored oligomeric products consisting of soluble (in benzene, chloroform) and insoluble fractions with yields amounting to 73 %. According to the data from ¹H NMR and IR spectroscopy oligomerization takes place mainly at the 1-vinyl group with partial involvement of the pyrrole ring. The process is accompanied by capture of the catalyzing acids by the azo group, leading to strong polarization of the elementary unit with transfer of positive charge to the pyrrole ring, which thus becomes capable of further transformations with cross-linking of oligomeric chains. The obtained oligomers possess electric conductivity of 10⁻¹³-10⁻⁹ S/cm, which is increased to 4.8∙10⁻⁶ S/cm when the products are iodinated with iodine vapor.