Issue 1/2022

Mzhachlkh I.E., Gorbunova I.Y., Kravchenko T.P., Chalaya N.M., Kolybanov K.Y., Shishkinskaya V.A.
Influence of thermoplastic elastomer additives on the properties of secondary polystyrene

Abstraсt: In recent decades, the experience of many countries has shown that waste management, especially in terms of their disposal, requires a state approach and the availability of a legislative framework. The solution of the issues of waste recycling of polymer materials is of urgent importance not only for environmental protection, but is also connected with the fact that with the existing shortage of polymer raw materials, plastic waste becomes an additional raw material and energy resource. The paper considers the physical and mechanical properties of composites based on modified secondary polystyrene formed after thermoforming food packaging from sheets of bioxyally oriented polystyrene. The effect of the modifier on the technological and strength properties of secondary polystyrene is shown. The addition of 1 to 5 wt. % maleinated thermoplastic elastomer to secondary polystyrene allowed to increase the fluidity of the modified composition by 2.6 times, reduce the viscosity of the melt, increase the impact strength by almost 3 times. The proposed method of modification of secondary polystyrene makes it possible to increase the productivity of the recycling process of secondary polystyrene, which is especially important when obtaining technical products by methods where shear flow is realized (injection molding and extrusion).

Keywords: polystyrene, waste, thermoplastics, modification, strength properties, viscosity.

Ivantsova N.A., Vetrova M.A., Kuzin E.N., Gavrilova N.N., Zakharova D.S., Bogomolov A.B., Zinin P.V.
Photo-oxidative degradation of nitrofural in the presence of graphite carbon nitride

Abstraсt: The unique properties of graphite-like carbon nitride are being actively studied by various scientific schools. Most of the scientific groups studying this topic belong to Europe and Asian countries. The number of developments in the Russian Federation is significantly inferior to foreign colleagues. One of the most promising areas of application of carbon nitride is catalysts for the photodegradation of organic substances, for example, in the process of wastewater treatment of pharmaceutical enterprises. Graphite-like carbon nitride is capable of displacing already existing known metal oxide catalysts, since it is a cheaper analogue and is capable of operating in the visible light region. As part of the work done, a study was made of the surface characteristics of a sample of graphite-like carbon nitride. The possibility of obtaining stable suspensions for static photocatalytic water treatment has been established. The possibility of oxidizing nitrofural using photocatalytic degradation processes in the presence of graphite-like carbon nitride has been proven.

Keywords: photocatalytic oxidation, carbon nitride, active pharmaceutical ingredients (API), oxygen-containing radicals, pharmaceutical waste.

Abdurakhmonov O.E.U., Alisultanov M.E, Vertaeva D.A., Sharapaev A.I., Muradova A.G.K.
Chemical method of synthesis of Nd2Fe14B nanopowders

Abstraсt: The paper presents a description of a new chemical method for the synthesis of Nd2Fe14B magnetic nanopowders. Permanent magnets based on the Nd-Fe-B alloy have increased magnetic abilities, and therefore are widely used in many techniques. At the first stage of the study, the following nanoparticles were synthesized by the chemical compound method: Nd2O3, Fe2O3, and Fe3BO6. The following were found: Nd2O3 nanorods with an average length of 118 nm and an average length of 28 ± 2 nm, Fe2O3 nanoparticles with an average length of 59 nm, Fe3BO6-3a-Fe2O3 nanoparticles with a quantitative determination of Fe2O3 – 74.4% and Fe3BO6 – 25.6% have an average size, diameter 65 nm. At the second stage of the reaction, the powders were mixed in stereochemistry to obtain Nd2Fe14B and reduced at 900°C in Ar + 5% Fl2. For complete reduction and formation of Nd2Fe14B particles, calcium hydride CaH2 is added to the mixture of powders, the resulting mixture is pressed into tablets, and a reduction-diffusion process is carried out at 800°C in an Ar medium. Nd2Fe14B nanopowder was obtained for the separation reaction from calcium oxide CaO, which is washed with a solution of ammonium chloride in ethanol NH4CI/C2H5OH. The developed method makes it possible to obtain nanopowders with a high frequency of Nd2Fe14B with an average value of 95 nm. The XRD results confirm the high efficiency of the method for obtaining Nd2Fe14B nanopowders.

Keywords: chemical synthesis, precipitation, reduction-diffusion process, neodymium magnets, nanopowders.

Antonova M.M., Kondratenko S.M., Kostikova N.A., Korneeva O.I., Shibkov O.O., Cherenkov M.A., Klimov D.I., Prikhod’ko V.V.
A new method for the production of diisopropylxanthogendisulfide using hydrogen peroxide as an oxidant

Abstraсt: Diisopropylxanthogen disulfide is in demand as a polymerization regulator in the production of rubbers. Known methods for its production have the following disadvantages: high corrosiveness of the reaction components, the presence of oxidizing impurities in the product due to their incomplete conversion, a long synthesis time, and others. The developed new method for the production of diisopropylxanthogen disulfide by the interaction of isopropyl potassium xanthate, phosphoric acid and hydrogen peroxide in water is free from the above disadvantages. It is optimal to carry out the process at a temperature of 30-35°C and a ratio of potassium isopropyl xanthate: H3PO4: H2O2 equal to 1 :1 :0.55 (equiv.), which makes it possible to achieve a yield of more than 90%. In the proposed new method for the synthesis of diisopropyl xanthogen disulfide, solvent recovery is ensured and the amount of waste generated is reduced. The use of a mixture of phosphoric acid and hydrogen peroxide as an oxidizing agent in the reaction with isopropyl potassium xanthate helps to avoid the formation of toxic sulfur-containing byproducts, leads to the formation of low-hazard waste and determines the high degree of utilization of raw materials. The developed method is implemented on an industrial scale, the production capacity of diisopropylxanthogen disulfide is at least 2000 kg/year.

Keywords: diisopropylxanthogendisulfide, potassium isopropyl xanthate, orthophosphoric acid, hydrogen peroxide, oxidation.

Makhina V.S., Serov A.N., Asnis N.A., Vahramyan T.A., Kuznetsov V.V.
Regularities of deposition of copper-tin alloy from alkaline electrolytes

Abstraсt: The main regularities of alloy electrodeposition are considered and an overview of existing bronze electrolytes is given. It is shown that of all the existing electrolytes at the moment, only cyanide-containing baths provide stable performance and high quality coatings. In this regard, interest in the development of stable cyanide-free electrolytes for obtaining coatings with a copper-tin alloy is quite high. It is shown that yellow bronze coatings with a tin content of 8-14% can be obtained from an alkaline cyanide-free electrolyte based on nitrilotrimethylphosphonic acid in a wide range of current densities. The estimation of conditional constants of stability of copper (II) and tin (IV) complexes formed in electrolytes is carried out. It was found that coatings with a copper-tin alloy from an electrolyte based on ATMP can be obtained despite the absence of convergence of the potentials of copper and tin. Electrodeposition of bronze, alkaline electrolytes, ATMP, aminotris(methylenephosphonic acid), stability constants of complexes.

Keywords: electrodeposition of bronze, alkaline electrolytes, ATMP, aminotris(methylenephosphonic acid), stability constants of complexes.

Ermolin I.K., Popov P.I., Kovaleva K.I., Mikhaleva M.G., Voronina L.I., Politenkova G.G., Nikolsky S.N., Lin A.A., Zlenko D.V., Stovbun S.V.
Development of new technologies and production of fluff-cellulose and mcc from oil flax waste

Abstraсt: Oilseed straw (Linum usitatissimum) flax is not used in industry and must be burned or decomposed naturally in the field. However, it contains cellulose of a low degree of polymerization, which can be used in industry. The aim of the work was to develop optimal and affordable technologies for processing oilseed flax waste to replace imports and saturate the market with domestic products. In this paper, we describe a simple approach to separating oilseed flax straw fibers from bonfires based on the use of drums with soft bristles capable of processing dry straw directly in the field. This approach does not require preliminary stages of soaking and cutting, the stems can be processed as is, which significantly reduces processing time and cost. To isolate pure cellulose from the resulting fiber, a low-temperature atmospheric process was developed and tested in practice, allowing to obtain commercial cellulose, microcrystalline and FLA.

Keywords: linum usitatissimum, MCC (microcrystalline cellulose), fluff pulp, nanocellulose, production platforms, waste processing.

Cherepanova A.D., Chernyshova A.V., Kolobkov B.I., Sapunov V.N., Kozlovsky R.A.
A review of the technologies for production of synthesized hydrocarbon jet fuels

Abstraсt: Among the numerous environmental problems at the moment, the problem of global climate change stands out. In this regard, alternative energy is developing at an accelerated pace, new renewable energy sources are being developed, the use of which is aimed to reducing greenhouse gas emissions. In particular, technologies for producing liquid motor fuels from non-petroleum raw materials are being intensively developed and implemented. The current level of technological development makes it possible to obtain a wide range of synthetic hydrocarbons that can be used as fuels for both gasoline, diesel and jet engines. This review briefly describes the technologies for the production of synthetic kerosenes currently approved by the ASTM D 7566 standard and additionally identifies key areas for further developments in this area.

Keywords: synthesized hydrocarbons, jet fuels, alternative energy, alternative fuels, biofuels, biomass.