PhC-2022

E.A. Bogdanova, V.M. Skachkov, K.V. Nefedova
Institute of Solid State Chemistry of the Ural Branch of RAS

Abstract: The hardened composite material with a porous structure was obtained by mechanochemical synthesis of nanostructured hydroxyapatite synthesized by precipitation from an aqueous solution with reinforcing additives of zirconium dioxide and silicic acid. Food gelatin is used as a binder. The influence of the phase composition on the physico-chemical properties of coatings (adhesive strength, microhardness, specific surface area, microstructure) is estimated. It has been established that the use of composite material together with gelatin as a part of a bioactive coating makes it possible to increase its hardness and adhesive strength. A patent application has been filed for the developed bioactive coatings based on nanoscale hydroxyapatite and biogenic elements with a binding agent. The composition of the dry mixture based on hydroxyapatite has been developed, which ensures a long shelf life without negative consequences and creates simple transportation conditions. Dilution of the dry mixture with distilled water gives a suspension that is convenient to use for coating implants of any configuration.
Keywords: hydroxyapatite, composite materials, biogenic elements, gelatin, collagen, bioactive coatings, adhesion

V.K. Krut’ko, L.Yu.. Maslova, O.N. Musskaya, A.I. Kulak
Institute of General and Inorganic Chemistry of the National Academy of Sciences of Belarus

Abstract: Bioactive calcium phosphate composites were obtained, consisting of open-pore multiphase calcium phosphate foam ceramic based on α / β-tricalcium phosphate, β-calcium pyrophosphate, biomimetic apatite and 5% hydroxyapatite gel at a mass ratio (ceramic foam / hydroxyapatite gel) of 1:3 and 1:10. Preliminary modification of the calcium phosphate foam ceramic with biomimetic apatite in a concentrated SBF×5 solution allows increasing the static strength to 0,05 MPa with a slight decrease in porosity and maintaining the open-pore structure of polyurethane foam. Calcium phosphate composites have increased resorbability in SBF×5 and are resorbed 3–5 times faster compared to calcium phosphate foam ceramic. The presence of a significant amount of hydroxyapatite gel increases the rate of resorption of calcium phosphate foam ceramic and the ongoing processes of apatite formation with the participation of SBF×5 ions due to its high reactivity. The obtained calcium phosphate composites are used in regenerative treatments to fill bone defects in unloaded areas.
Keywords: calcium phosphate foam ceramic, tricalcium phosphate, hydroxyapatite gel, simulated body fluid, biomimetic apatite, resorbability

I.S. Medyankina¹, K.I. Svetlakova², L.A. Pasechnik^1
1 Institute of Solid State Chemistry of the Ural Branch of RAS
² Institute of Chemical Technology, Ural Federal University named after the first President of B.N. Yeltsin

Abstract: The synthesis of cobalt hydroxysilicate Co₃(Si2O₅)₂(OH)₂ in a matrix of high dispersity amorphous silica has been proposed. It is shown the formation of a hydroxosilicate, which combines coordinated silica and cobalt-oxygen polyhedrons in the overall structure, as well as the availability of surface hydroxyl groups, contribute to the preservation of a high specific surface area as is in amorphous SiO₂. The hydroxosilicate also contributes to the effective manifestation of photocatalytic properties due to the presence of cobalt (2+), which has a high reactivity. As methods of synthesis of SiO₂/Сo composites hydrochemical methods are used by impregnation and autoclave treatment with solution of cobalt formate of silica. The influence of the amount of introduced cobalt on the composition, structure, and properties of a composite material containing Co₃(Si₂O₅)₂(OH)₂ in a SiO₂ matrix has been traced. SiO₂/Co composites have been tested in the hydroquinone photooxidation reaction when exposed to ultraviolet radiation. The highest degree of hydroquinone decomposition amounting to 84% in 18 hours was achieved for SiO₂/Co at a molar ratio of components Co:Si = 0.01:1.
Keywords: amorphous silica, cobalt silicate, hydrothermal synthesis, mechanosynthesis, microstructure, photocatalysis, hydroquinone

O.N. Musskaya, V.K. Krut’ko, A.I. Kulak, E.N. Krutsko
The Institute of General and Inorganic Chemistry of the National Academy of Sciences of Belaru

Abstract: Etherification of the surface of cellulose carriers with phosphoric acid in the presence of urea yielded fiber materials characterized by an increased degree of swelling in aqueous media (by a factor of 1,1-1,5). The copper nanoparticles and their composites with amorphized calcium phosphates were synthesized by the borohydride method using the sodium salt of carboxymethyl cellulose as a stabilizer polymer. The obtained colloidal solutions of copper and their composites with hydroxyapatite are characterized by stability from several days to 2 months. It was found that the modification of cellulose materials (initial and phosphorylated) by the immersion method using aqueous compositions containing amorphized calcium phosphates, copper nanoparticles or composites based on them in the presence of sodium carboxymethylcellulose and ascorbic acid at pH 6 and 11 leads to a decrease in the crystallinity of the polymer carrier. It has been shown by IR spectroscopy that the amorphization of modified fiber cellulose materials is due to a change in the static homogeneity of the system of hydrogen bonds in the polymer structure.
Keywords: cellulose, phosphorylated cellulose, sodium carboxymethylcellulose, amorphized calcium phosphates, hydroxyapatite, copper nanoparticles

A.A. Ostroushko, T.Yu. Zhulanova (Maksimchuk), E.V. Kudyukov, I.D. Gagarin, O.V. Russkikh
Ural Federal University named after the first President of Russia B.N. Yeltsin

Abstract: Lanthanum manganite doped with strontium samples were synthesized by the combustion method of nitrate-organic precursors of different composition. The combustion process was realized under the influence of an external alternating electromagnetic field and in its absence. It was found that thermochemical generation of charges occurs during precursor’s combustion, recorded as a potential difference of precursor-earth. It is shown that the composition of the initial precursor (organic component and its quantity), as well as the presence of an external alternating electromagnetic field, affect the magnitude of the potential difference that occurs, varying from -7 to 125 V. The relationship between the studied electromagnetic properties (saturation magnetization, coercive force, Curie temperature) of the obtained samples and the precursor–earth potential difference arising during synthesis is shown. The Curie temperature values varied in the range of 38-79°C for samples obtained under the influence of an alternating electro-magnetic field, and 49-104°C in its absence.
Keywords: Complex oxides, lanthanum manganite, synthesis, combustion reactions, charges, electromagnetic field, magnetic properties

A.A. Ostroushko¹, S.Yu.. Menshikov², D.A. Rozhentsev³, N.K. Tkachev³, A.Ya.. Golub¹, M.O. Tonkushina^1
1 Ural Federal University named after the first President of Russia B.N. Yeltsin
² Ural State Mining University
³ The Institute of High Temperature Electrochemistry of the Ural Branch of the Russian Academy of Sciences

Abstract: We have revealed the catalytic activity for initiating the water-emulsion turpentine polymerization of some nanostructured materials such as Keplerate type Mo₇₂Fe₃₀ nanocluster polyoxometalate, nanoporous iron and nanoporous composite of intermetallic compounds Pd₂In@Pd₃In obtained by dealloying of equiatomic alloys Fe – Mn and Pd – In. For polyoxometalate solutions and nanoporous metal samples, respectively, the yield of sufficiently pure polyterpene resins when using the potassium persulphate initiation depends on the nature of the contact between the catalysts and substrates: solid-liquid-liquid or liquid-liquid. A system that did not contain catalysts was taken as the reaction medium for comparison. Based on the obtained data on the softening point, the molecular weight of the resin samples was determined. Infrared spectroscopy was used to identify the obtained products. In the reaction medium (mainly aqueous) after the isolation of polyterpene resins, chromatographic analysis revealed so valuable products as alpha-terpineol, which is used as an intermediate for obtaining flavors and flotation agents.
Keywords: Nanostructured initiation catalysts, polyoxometalates, metals, emulsion polymerization, turpentine, polyterpene resins, potassium persulfate

N.V. Permiakov, A.I. Lebedeva, E.V. Maraeva
Saint Petersburg Electrotechnical University «LETI»

Abstract: The work is devoted to the search for a scientific and technical solution for the creation of filaments based on hydroxyapatite and polycaprolactone for extrusion three-dimensional printing. Hydroxyapatite powders were obtained by chemical precipitation using microwave radiation, and the average particle size in the powder was determined. Options for creating a filament by extrusion based on a composition of hydroxyapatite and polycaproloctone for subsequent printing of scaffolds (temporary scaffolds necessary for the formation of new functional tissues) are proposed. Images of the surface of calcium hydroxyapatite were obtained using a scanning probe microscope to assess the parameters of surface roughness, which is one of the most important factors for successful cell adhesion to the scaffold surface during osseointegration processes.
Keywords: hydroxyapatite, polycaprolactone, 3D printing, nanocomposite, scaffold, scanning probe microscopy

V.K. Krut’ko, A.E. Doroshenko, O.N. Musskaya, A.I. Kulak
Institute of General and Inorganic Chemistry of the National Academy of Sciences of Belarus

Abstract: Calcium phosphate composite powders consisting of brushite and calcite were obtained in an aqueous medium from a CaCO₃/Ca(H₂PO₄)₂ suspension at Ca/P ratios of 1,33, 1,50, 1,67, pH 5–7, and maturation time of 21-50 days. Prolonged maturation (up to 68 days) of composite calcium phosphate powders led to a hydrolytic transition of brushite to octacalcium phosphate, the amount of which increased with increasing duration of the maturation stage. Drying calcium phosphate powders at 37°C for 24 h contributed to the partially transition of the metastable phase of octacalcium phosphate to apatite represented by amorphous calcium phosphate. The presence of vibrations of О–Н at 633 cm^-1 as the shoulder on the IR spectra indicates the presence of apatite in calcium phosphate powders. The use of an electric current (20 mA/cm², 3–20 min) for a local increase of the pH value made it possible to increase the amount of octacalcium phosphate in the composition of the composite powder, which has a characteristic rosette morphology of thin lamellar crystallites.
Keywords: octacalcium phosphate, calcite, monocalcium phosphate monohydrate, brushite, apatite, hydrolytic maturation

K.G. Savina, I.R. Galuzin, A.Yu.. Kolosov, S.S. Bogdanov, A.D. Veselov, N.Yu.. Sdobnyakov
Tver State University

Abstract: This work studied bimetallic nanoparticles Ni@Ag and Ag@Ni with the total number of atoms 4000 by the molecular dynamics method using the tight-binding potential. The pattern of segregation and structural formation is established and its characteristics are described. Based on the analysis of the behavior of the calorie curves of the potential part of the internal energy, the melting and crystallization temperature was determined. The data obtained suggest that the processes of segregation in Ni@Ag and Ag@Ni nanoparticles are associated with the nanoparticle stability. The silver shell loses its stability above 900 K, while the nickel core remains solid and retains its structure. At the same time, in Ni₆₇₅@Ag₃₃₂₅ nanoparticles the processes of the surface segregation of the nucleus atoms were less pronounced, whereas in Ag₆₇₅@Ni₃₃₂₅ nanoparticles silver atoms actively segregated onto the surface of the nanoparticle. The features and fundamental differences in the processes of melting and crystallization of these nanosystems, as well as the temperature ranges of their stability, are analyzed. The relationship between the degree of intensity of segregation processes of nanoalloys during modeling and the stability of these systems is shown.
Keywords: molecular dynamics method, bimetallic nanoparticles, nickel, silver, segregation, structure formation, stability, core-shell

D.A. Kravchenko, O.N. Medvedeva
Tver State University

Abstract: In recent times, 3D printing technologies are a young and actively developing production sector for many areas of economy, from aerospace and mechanical engineering to medicine. The obvious advantage of introduction of the additive technologies in medicine and in particular in dentistry is high accuracy in producing complex details, individually designed implants and prostheses for their maximum match with a place of injury or a substituted object, considerable reduction both the product materials and auxiliary materials usage. However, questions arise about the limits of applicability and reliability of the additive technologies with their active introduction. The properties of dental crowns made of nickel-chromium alloy NH-Dent NS vac and cobalt-chromium powder PR-KH28M6 were studied in this research. For the production of samples was used selective laser melting technology, which belongs to a number of additive technologies, and the casting technology in the mold. A comparative analysis of the microstructure of the samples, the surface profile and the Vickers hardness was carried out.
Keywords: additive technologies, medicine, dentistry, selective laser melting technology, selective laser melting, microstructure, surface profile, hardness of samples