Abstraсt: Hybrid polyurethane-urea nanocomposites containing 0.3-3 wt.% silver nano-particles were obtained by in situ reduction of silver nitrate in a solution of polyurethane-urea copolymers. The effect of silver nanoparticles concentration on the structure and crystallization of composites has been studied. It was found that the introduction of silver nanoparticles accelerates crystallization, which allows to adjust the rate of fixation of the material shape after cooling or stretching.
Keywords: polyurethane urea thermoplastic copolymer, silver nanoparticles, crystallization kinetics, crystal structure.
Abstraсt: Polymer nanofibers are materials with superior properties compared to microfibers. Electroforming is currently the easiest and most efficient process for fabrication nanofibers. However, during the electrospinning process, the characteristics of the polymer solution have a significant effect on the formation of fibers. This paper presents the dependence on polyvinyl chloride concentration of the dynamic viscosity, the surface tension, and the electrical conductivity of this polymer solutions with different molecular weights in a mixture of dimethylformamide and tetrahydrofuran solvents. An increase in the concentration of polyvinyl chloride from 5 to 25 mass. % leads to an increase in viscosity and electrical conductivity. In this case, the surface tension varies slightly over the entire range for both molecular masses but has a pronounced maximum. The obtained results will allow to control the diameter of the electrospun nanofiber in the process electrospinning.
Keywords: polyvinyl chloride, rheology, viscosity, shear stress, electrical conductivity, surface tension, electrospinning, nanofibers.
Abstraсt: The structure and profiles of the concentration distribution in the transition zones of the formed adhesion joints based on polyamide-6(pa-6) and maleized polyethylene (таре) were found by electron probe x-ray spectral microanalysis. The thermo-chemical and energy characteristics of individual components was determined. We also look at the influences of temperature and contact formation time on mechanical properties adhesive systems.
Keywords: transition zones, maleated polyethylene, compatibilizer.
Abstraсt: In this work, an alternative to indium tin oxide is developed: an electrically conductive coating is created on the glass. The developed coating will have good transparency. The basis of the coating is oriented networks of nano- and submicron nickel wires. Nickel is a good conductor of electrical current. The basis of the technique is the precipitation from the liquid phase by chemical reduction of a nickel salt. The use of an external magnetic field makes it possible to obtain a long-range order orientation. The nickel nanowires synthesized in this work have a height of less than 10 nm and a width of about 30 nm. Elemental analysis of nanowires was carried out using a transmission electron microscope with an energy dispersive attachment. Submicron nickel fibres are also synthesized in a magnetic field by chemical reduction of nickel chloride. It was made to create the second level of the network. The submicron network should provide a supporting framework for oriented nanonetworks and establish electrical contact between the domains of oriented nanonetworks. The surface resistance of the obtained coating on the glass surface was studied by the standard van der pauw technique of four-probe measurements.
Keywords: nanowires, nanonetworks, conductive coating, nickel.
Abstraсt: Colloidosomes are prepared by self-assembly of detonation nanodiamonds on “water / oil” interface. Two types of energy-intensive materials are encapsulated into shells made of nanodiamonds and surfactants: a hydrocarbon (eicosane) and a crystalline hydrate (mg (no3) 2 – 6h2o). The shell composition is investigated on thermal properties.
Keywords: pickering emulsion, detonation nanodiamonds, self-assembly, colloidosomes, crystal hydrates, phase batteries.
Abstraсt: Physics and chemistry of the process of producing syntactic foams, which are a mixture of a hollow filler with a hollow thermoplastic binder, for the purpose of its use in various industries for filling ultralight structures.
Keywords: syntactic foam, physics and chemistry of the formation process, thermoplastic hollow binder, hollow filler.
Abstraсt: Isocyanates are one of the most demanded products of the chemical industry, as they are raw materials for the production of polyurethanes, the quality of which is influenced by the purity of isocyanates. The main production of isocyanates is based on the conversion of the amino group to the isocyanic one. This work is devoted to the analytical control of mdi (methylene diphenyl diisocyanate).
Keywords: mda, methylene diphenyldiamine, mdi, isocyanates, methylene diphenyl diisocyanate, polyurethanes.
