PERSPEKTIVNYE MATERIALY
2023, No.4
Traditional and new approaches
to the creation of biomedical materials based
on polyhydroxyalkanoates
with antimicrobial activity
P. M. Tyubaeva, A. A. Popov, A. A. Olkhov
This thematic review considers the principles of creating biomedical materials based on biopolymers and their compositions for various medical needs. The direction of creating materials with antimicrobial activity is especially emphasized using the example of polyhydroxyalkanoates. These biopolymers and composites based on them occupy leading positions in the production of medical devices. Polyhydroxyalkanoates as a class of biopolymers, as well as polyhydroxybutyrate, the most suitable representative of this class for biomedical products, were analyzed from the point of view of increasing resistance to microorganisms. Progress in this direction has been reported in recent years. The influence of the supramolecular and molecular structure of materials on the ability to biodegrade in the environment and in a living organism is considered in sufficient detail. The advantage of mixtures of biopolymers for achieving high degradation rates compared to the original polymers was noted. Promising antiseptics based on porphyrin metal complexes in combination with biopolymer nonwoven fibrous matrices have been demonstrated. Features of preclinical tests of antiseptic materials are considered. Based on this review of research papers, it can be concluded that the structural organization of a polymeric material or composite determines the level of intermolecular interactions during the formation of the material and thereby programs the complex of functional properties and the degradation mechanism under the influence of aggressive external factors.
Keywords:polyhydroxyalkanoates, poly-3-hydroxybutyrate, antimicrobial, microbial resistance, porphyrin metal complexes.
DOI: 10.30791/1028-978X-2023-4-5-30
Ion-beam formation of a silver-containing surface
of porous silicon
V. V. Perinsky, I. V. Perinskaya, I. V. Rodionov,
L. E. Kuts
The results of a study of the formation of a silver-containing porous layer on the surface of single-crystal silicon KEF-4,5 by ion-beam alloying are presented. A computer simulation of the process of ion doping of silicon with KEF-4,5, high-energy helium and silver ions was carried out using the TRIM/SRIM software package in order to determine the dose and energy neighborhoods of helium and silver ions necessary and sufficient in the experiment. The relief of the porous surface, the density of quasi-pores on the surface of implanted silicon, the elemental composition of the obtained porous composite silver-containing layers, taking into account the effect of intermediate heat treatment on it, are studied. The ion-beam formation of a silver-containing coating ensures the creation of a developed surface relief at the nanoscale with high reproducibility and controllability inherent in the ion doping method, which contributes to an increase in the yield of usable solar cell products. The technological modes of high reproducibility and controllability inherent in the ion doping method are determined based on the experimental data obtained for studying the relief of a porous surface and the density of quasi-pores on the surface of implanted silicon from the energy and dose of helium ions. Based on the study of the elemental composition of the quasi-porous composite silver-containing layer obtained by implantation of silver ions, the recommended parameters of implantation of silver ions have been established.
Keywords:silver ions, helium ions, porous silicon, ion-beam alloying, TRIM/SRIM software package, composite silver-containing layer.
DOI: 10.30791/1028-978X-2023-4-31-41
Research of nanosized iron oxide powder
as a biologically active material
V. S. Kataev, M. A. Fedotov, N. A. Andreeva,
A. A. Fomina, V. A. Volchenkova, A. A. Alpatov
A polydisperse nanopowder of iron oxide, consisting of hematite α-Fe2O3 and magnetite Fe3O4, was obtained by the method of solid-phase reduction of iron hydroxide Fe(OH)3. On the basis of the obtained iron oxide nanopowder, aqueous suspensions were prepared in the concentration range of 0.25 – 1.25 mg/l with a particle dispersion of 100 – 400 nm. To assess the biological activity of iron oxide nanopowder, pre-sowing treatment of corn seeds Zéa máys was carried out. It has been established that the treatment with nanoparticles has a stimulating effect on the development of the plant organism, making it possible to achieve an increase in germination by 15% and root mass by 23%. Determination of the quantitative content of iron in different parts of the plant was carried out using atomic emission and atomic absorption spectroscopy. It was shown that as a result of treatment of plants with iron nanoparticles, its accumulation in the root mass with subsequent redistribution to the leaves to stimulate the process of photosynthesis is observed.
Key words:nanoparticles iron oxide, solid-phase reduction, biological activity, atomic emission spectroscopy, atomic absorption spectroscopy.
DOI: 10.30791/1028-978X-2023-4-42-49
Investigation of the influence of carbon fillers
on the manifestation of the effect
of tensoresistivity in tire regenerates
N. V. Shadrinov, K. P. Antoev
An opportunity of development of electrically conductive rubber based on industrially produced tyre regenerate RShT-4 and Reg-1, obtained in laboratory conditions, with electrically conductive carbon fillers is shown. OMCARB CH85 carbon black (CB) produced by “Omsktehuglerod” Ltd. and Tenax-e HTS-45 carbon fibres (CF) produced by Toho Tenax America were used as electrically conductive fillers. Curing and rheometric properties of regenerates with different content of Santogard PVI and electroconductive fillers have been investigated. The study of physical and mechanical properties of regenerates has shown that introduction and increase of electroconductive CB and CF content in Reg-1 and RShT-4 leads to gradual reduction of elongation at break and increase in tensile strength and Shore A hardness, which is evidence of reinforcing effect of fillers. The effect of tensoresistance in the obtained regenerates depending on the content of electroconductive fillers is investigated. It is shown that addition of electroconductive CB to Reg-1 and RSHT-4 gives electroconductivity and tensoresistivity, that is, decrease of resistance in compression. Addition of CF leads to the opposite effect - increase of electrical resistance in compression. The possible mechanisms for the manifistation of tensoresistance at introduction of electroconductive CB and decrease of electroconductivity at introduction of CF are offered.
Key words:tyre regenerate, curing properties, electrical conductivity, strain resistance, carbon fibres, electrically conductive carbon black.
DOI: 10.30791/1028-978X-2023-4-50-59
Technology and properties of high-temperature
piezoceramic materials based on phases
of the system (1 – у)(Bi0.8Ba0.2)Fe0.8Ti0.2O3
– у(Ba0.85Ca0.15)Ti0.90Zr0.10O3
А. A. Nesterov, M. I. Tolstunov
In technology, using as precursors Fe(III) and Bi(III) nitrates, peroxo-nitrate complexes Ti(IV) and Zr(IV), as well as barium and calcium hydroxides, ultrafine powders of the (1 – у)Bi0.8Ba0.2Fe0.8Ti0.2O3 – уBa0.85Ca0.15Ti0.9Zr0.1O3(у = 0,05 – 0,30). To reduce the electrical conductivity of ceramic samples made from these powders, the basic phases were alloyed with manganese compounds. To increase the d33 values of the piezoelectric elements, as well as to increase their operating temperature, a special sintering regime involving air hardening of the ceramic samples was used. The best samples of piezoceramics produced by the proposed technology have a Curie temperature above 550 °C and longitudinal piezoelectric modulus (standard conditions) values d33 ≥ 125 pC/N and their operating temperature reaches 340 – 350 °C.
Keywords:piezoelectricity, ferroelectricity, synthesis, lead-free material.
DOI: 10.30791/1028-978X-2023-4-60-67
Synthesis and catalytic activity
of highly dispersed solid solutions Ce0,9Sn0,1O2
and Ce0,8Sn0,1Zr0,1O2 in CO oxidation
E. A. Simakina, E. Y. Liberman, B. S. Kleusov,
T. V. Kon’kova, V. N. Grunskii, A. N. Morozov, A. V. Denisenko
Fluorite-like solid solutions of Ce0.9Sn0.1O2 and Ce0.8Sn0.1Zr0.1O2are synthesized by co-precipitation using ammonium carbonate as a precipitant. The samples were characterized by X-ray phase analysis, electron microscopy, energy dispersive analysis, low-temperature nitrogen adsorption, and gas chromatography. It is shown that the formation of solid solutions occurs even at an annealing temperature of 550°C. In this case, the formation of lamellar particles occurs, the size of which, according to SEM data, is 4 μm. The synthesized materials have a mesoporous structure. The specific surface area of Ce0.9Sn0.1O2samples is 80.6 m2/g, Ce0.8Zr0.1Sn0.1O2is 76.3 m2/g. Carrying out the calcination at a temperature of 800 °C leads to an increase in the particle size up to 8 – 10 µm. The highest specific surface area of 15.3 m2/g is typical for the Ce0.8Zr0.1Sn0.1O2sample, which is due to the presence of zirconium ions in its composition. The synthesized compositions demonstrated high activity in CO oxidation. The maximum catalytic activity was observed for the bicomponent system Ce0.9Sn0.1O2: T50% — 180°C, T90% — 236 °C. For samples calcined at a temperature of 800 °C, the most active is Ce0.8Zr0.1Sn0.1O2, which is due to the formation of a more thermally stable system compared to cerium dioxide and Ce0.9Sn0.1O2. To increase the thermal stability, it is advisable to dope the bicomponent composition Ce0.9Sn0.1O2with Zr+4 ions.
Keywords: cerium dioxide, solid solutions, CO oxidation.
DOI: 10.30791/1028-978X-2023-4-68-75
Spark Plasma Sintering of ultrafine-grained
WC – Al2O3 ceramics
E. A. Lantsev, A. V. Nokhrin, M. S. Boldin,
K. E. Smetanina, A. A. Murashov, Yu. V. Blagoveshchenskiy,
N. V. Isaeva, G. V. Shcherbak,
V. N. Chuvil’deev, N. Yu. Tabachkova, A. V. Terentyev
The sintering mechanisms of WC – Al2O3 nanopowder compositions with different contents of aluminum oxide particles (1, 3, 5 wt.%) were investigated. Samples of WC – Al2O3 ceramics were produced by Spark Plasma Sintering method (SPS) in vacuum, by heating to a temperature of 1450 °C at a rate of 50 °C/min under uniaxial stress 70 MPa. Plasma-chemical nanopowders of tungsten monocarbide and submicron powders of aluminum oxide were used to make the ceramics. The density, microstructure, phase composition, microhardness (Hv) and fracture toughness (KIC) of the ceramics were investigated. It was shown that the use of the SPS method makes it possible to obtain WC-Al2O3 ceramics with good relative density (95.4-98.1%) and a homogeneous microstructure with ultrafine grain size (0.1 – 0.2 μm). By the method of the X-ray phase analysis, it was established that in the process of SPS of WC-Al2O3 ceramics the formation of an undesirable W2C phase takes place, leading to decrease in the fracture toughness KIC. To reduce the intensity of W2C particle formation, colloidal graphite (0.1, 0.2, 0.3 wt.%) was added to WC – Al2O3 ceramics. Using the Young-Cutler model and the model of diffusion resorption of pores it was shown that the main mechanism of SPS of WC – Al2O3 ceramics is grain boundary diffusion. It is shown that the introduction of graphite leads to a decrease in the activation energy of SPS of WC – Al2O3 ceramics, which is probably due to a decrease in the W2C particle content to 0.5 wt.%.
Keywords: tungsten carbide, aluminum oxide, spark plasma sintering, density, grain size, diffusivity.
DOI: 10.30791/1028-978X-2023-4-76-88
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