Sulfurization polyvinyl chloride

A sulfurized polymer comprising 57.64% of chemically bound sulfur characterizing by paramagnetism with the concentration of paramagnetic centers 2 × 10¹⁹ spins g^?1 and g-factor 2.0043 was resulted n the treatment of industrial polyvinyl chloride by elemental sulfur.     

Preparation and properties of polyvinylenepolysulfides based on trichloroethene and sodium polysulfides

Interaction of trichloroethene with sodium tetra- and pentasulfide (prepared in turn from sodium sulfide and elemental sulfur) has lead to new family of polyvinylenepolysulfides containing up to 94% of sulfur. The polymers were found highly electrochemically active when applied as active cathode for lithium batteries.     

Immunomodulatory properties of silver-containing nanocomposite on the basis of polyvinyltriazole

Russian Chemical Bulletin - The water-soluble nanocomposite with the uniform distribution of silver nanoparticles in polymer matrix was synthesized on the basis of poly-1-vinyl-1,2,4-triazole....     

Metal-polymer Ag nanocomposites based on hydrophilic nitrogen- and sulfur-containing copolymers: control of nanoparticle size

Russian Chemical Bulletin - New polymer nanocomposites containing silver nanoparticles, stabilized by hydrophilic copolymers of 1-vinyl-1,2,4-triazole with vinylsulfonic acid sodium salt of...     

Sulfur-containing polymer and carbon materials based on poly(vinyl chloride)

New sulfur-containing copolymers based on poly(vinyl chloride) have been prepared by the nucleophilic substitution of chlorine atoms by sulfur atoms using sodium tetra- and pentasulfides. It has been shown that these copolymers can be carbonized to produce sulfur-containing carbon materials with residual chlorine content about 2 wt %.     

Investigation of the hyperfine interaction in the antiferromagnetic CsMnI3

The lower branch of the resonance spectrum of the quasi-one-dimensional triangular antiferromagnetic CsMnI₃ has been investigated experimentally. This branch possesses a gap due to the dynamic hyperfine interaction. The temperature dependence of the energy gap was studied in detail at several frequencies. A theoretical calculation of the corresponding spectrum of coupled electron-nuclear spin oscillations was performed in the “hydrodynamic approximation” with an empirical correction for thermal fluctuations of the antiferromagnetic system. The good agreement between the calculation and experimental data makes it possible to determine the zero-point spin reduction in the antiferromagnetic. Zh. éksp. Teor. Fiz. 112, 1893–1898 (November 1997)     

Functional copolymers with triazole and acetate fragments

New functional copolymers of different composition with triazole and acetate fragments in the macromolecules were synthesized by free radical copolymerization of 1-vinyl-1,2,4-triazole with vinyl acetate. The reactivity of the comonomers was studied and the monomer copolymerization constants were calculated. The structure and composition of the copolymers were determined by elemental analysis, IR and ¹H NMR spectroscopy.     

Fe-containing nanocomposites based on a biocompatible copolymer 1-vinyl-1,2,4-triazole with <Emphasis Type="Italic">N</Emphasis>-vinylpyrrolidone

New polymer nanocomposites containing iron oxide nanoparticles stabilized with a biocompatible copolymer of 1-vinyl-1,2,4-triazole with N-vinylpyrrolidone were produced. The synthesis was conducted using the method of chemical reduction of iron ions with hydrazine hydrate in an aqueous medium in the presence of a polymer matrix. The ESR spectroscopy data showed that the core—shell type nanoparticles were obtained. The core generally consistsed of zero-valence iron coated with an oxide shell. According to the data of transmission electron microscopy, the obtained polymer nanocomposites consisted of nanoparticles of mainly spherical shape with a diameter from 1 to 14 nm. Aggregates formed from individual stabilized nanoparticles of up to 75 nm in size (in most cases) were also observed. These aggregated particles were found to self-organize and form branched chains. Nanocomposites were characterized by a different particle-size distribution, which was determined by the initial ratio of the copolymer and the precursor of iron nanoparticles.     

Decomposition of teflon heat protective coatings at hypersonic flight velocities

We consider the decomposition of a teflon thermal protective coating along the generatrix of a blunted solid of revolution for various Mach numbers and pressures of the incident flow. On the basis of preliminary parametric study of the equations of a laminar boundary layer with pressure gradient, calculation of the teflon decomposition parameters is reduced to solution of a system of nonlinear and transcendental equations. It is shown that the temperature distribution and decomposition rate along the generatrix of the solid of revolution have a monotonie character, and that the effective enthalpy of the material remains constant along the body. A simple approximate formula is proposed for calculation of the teflon decomposition rate.     

New magnetic states in copper metaborate CuB<Subscript>2</Subscript>O<Subscript>4</Subscript>

The static and resonance properties of copper metaborate CuB₂O₄ were experimentally studied in a magnetic field applied in the crystal tetragonal plane. The field-induced second-order phase transition to a weakly ferromagnetic state was observed in the temperature range 10–20 K. The low-field state is characterized by the absence of spontaneous moment, and it represents, presumably, a long-period helicoid. At temperatures below 2 K, two sequential first-order phase transitions were observed. They were accompanied by jumps in resonance absorption with a hysteresis upon changing field-scan direction. These transitions can be caused by the transformation of the incommensurate spin structure into the helicoidal states with periods commensurate with the lattice translation period.