This study investigates the effect of controlled acid demineralization of coal shale from Shubarkol Komir JSC using HCl solutions with concentrations of 9–37% by mass on its structural characteristics, the kinetics of thermal decomposition, and the ability to concentrate rare and dispersed trace elements in the solid residue from the hydrodemetallization of the heavy fraction of coal tar. Analysis of IR spectroscopy, TG/DTG and isoconversional kinetics showed that acid treatment leads to the removal of carbonate and partially iron-containing phases while maintaining the aluminosilicate framework, increasing the structural uniformity of the matrix and moving to a more ordered thermal decomposition mechanism. The activation energy in the range of α = 0.1–0.7 is 83–87 kJ/mol for all modified samples, increasing to 96.20 kJ/mol at α = 0.9 for CS100. It has been established that the ability of coal shale to concentrate rare and dispersed trace elements in the solid residue of hydrodemetallization changes non-monotonically: the total content of trace elements reaches a maximum of 1452.19 g/t with moderate acid treatment (CS50) and sharply decreases to 137.85 g/t with deep demineralization (CS100). It has been shown that the degree of acid treatment acts as a controlled parameter that allows for purposefully regulating the ability of coal shale to concentrate rare and dispersed trace elements in the process of hydrodemetallization of heavy hydrocarbon raw materials.

This study presents an integrated approach to processing the heavy fraction of coal tar (HFCT) using oil shale (OS) from Shubarkol Komir JSC to simultaneously increase the yield of valuable hydrocarbon fractions and extract rare and dispersed trace elements. The lack of data on the effect of shale on the process and the kinetics of multi-component “tar + shale” systems limits the development of effective technologies. TG/DTG analysis was combined with the Friedman, Ozawa–Flynn–Wall, and Šesták–Berggren methods for the first time to evaluate the role of oil shale (OS). It was shown that the addition of 13% OS provides a sustained reduction in activation energy (~85–86 kJ/mol) and optimal conditions for hydrometallization. At 420 °C, an initial H2 pressure of 4 MPa, and a reaction time of 60 min, the yield of light fractions reaches 62.6%, and the solid residue concentrates Ti, Mo, Ge, and other rare and dispersed elements reach up to 66,000 g/t in total. The possibility of extracting Ge using the Purolite C100 sorbent has also been confirmed. The novelty of the study lies in demonstrating the donor–catalytic effect of shale and the practical prospects of solid residue as a secondary mineral raw materials.

Thermal behavior of low-temperature coal tar modified with two additives -1% converter slag catalyst (Fe and Ti oxides) and 1% polyethylene was investigated. The purpose of the study was to determine the effect of double modification on the kinetics of thermal decomposition and the stability of the material. TG/DTG analysis showed that the modified coal tar decomposes predominantly via a one-step mechanism, with a peak decomposition rate at similar to 270 degrees C. Kinetic parameters calculated using the Coats - Redfern method indicated that the third-order reaction model best fits the data (R-2 = 0.996), with an activation energy of 42 kJ/mol. To improve accuracy, a non-parametric kinetics (NPK) method based on singular value decomposition (SVD) was applied, enabling isolation of the dominant decomposition stage and identification of reactive temperature zones. The kinetic behavior was also found to vary with heating rate due to changing contributions from secondary components. The results obtained demonstrate the high thermal activity and structural complexity of the modified tar, and also confirm the effectiveness of an integrated approach to the analysis of thermokinetics. The work can serve as a basis for the further development of fire-resistant, electrically insulating and carbon-based bonding materials with controllable characteristics. [GRAPHICS] .

Previous studies investigating the thermal decomposition of p-PGFPh:AA copolymers in an inert atmosphere have provided only a general understanding of the changes that occur during thermolysis. Comprehensive studies are required to gain a better understanding of these processes [1]. The most comprehensive information on the influence of various factors on both the kinetics and the supramolecular structure of the resulting products can be obtained by combining the method of thermal analysis with IR, mass spectrometry, and scanning electron microscopy. The compounds studied have two different compositions, namely p‑PGFPh:AA 6.77:93.23 mol % and p-PGFPh:AA 86.67:13.33 mol %. These compounds were then subjected to a thermolysis process, which resulted in the emission of gases and a decrease in sample weight. The degradation process can be divided into three stages: 1) Depolymerization of the main chain; 2) Depolymerization of the side chain; 3) Final decomposition. These processes occur sequentially at different temperature ranges. According to TG- and DTG studies, complete decomposition of p-PGFPh:AA copolymers occurred at Tterm = 340–350 °C. In this temperature range, a slight loss of sample mass (less than 10 wt %) was observed along with a slight gas evolution. The main gaseous products from the transformation of the studied samples were CO and CO2. This was supported by IR-CO (2000–2200 cm−1) and CO2 (2310–2370 cm−1) as well as mass spectrometric observations. The final products resulting from the thermolysis of p-PGFPh:AA copolymers were examined under an electron microscope. The results showed a similar morphological pattern of mesostructures with sizes ranging from 0.3–1.5 μm, which were observed depending on the porous structure of the initial polymer material. Based on the experimental data, it can be concluded that the p-PGFPh:AA copolymers (in proportions of 6.77:93.23 mol % and 86.67:13.33 mol %) have a relatively high degree of resistance to heating and do not undergo any changes in chemical composition, particle size and shape. In conclusion, the results clearly indicate that the selection of conditions for pyrolysis plays a crucial role in increasing the thermal stability of polymeric materials. This method allows for purposeful changes in the structure and properties of polymers.

Understanding the physical and chemical properties of new-generation polymeric materials during the synthesis is very important in obtaining the desired product in design and production. Chemical, thermal, and physical parameters as well as degradation kinetics of the resins developed especially in recent years are the main stages that determine the polymer composition process that affects material selection. In this study, the potential to use RAFT agent (2-cyano-2-propyldodecyltrithiocarbonate, CPDT) in the synthesis of new polymers based on polypropylene fumarate phthalate has revealed important properties. To exemplify, the concentration of the RAFT agent affects the polymer-based mesh density associated with the yield of the product. Changes in swelling behavior and thermodynamic parameters of polymers synthesized in the presence of RAFT agent were observed. Chemical composition and stability characterizations of the synthesized grafted polymers were performed by FT-IR, 13C, 1H-NMR spectroscopy and TGA. The grafted polymers analyzed by SEM morphology were found to have hydrogel sorption potential showed signs of a loose surface and the formation of a layered and porous structure in comparison with the grafted polymers. The resulting compounds have a high swelling capacity and increased yield. At the same time, this study will shed light on the thermodynamic calculations of the graft polymers in order to determine or predicting the polymer composition.

The laws of thermal degradation of the mixture of the heavy fraction of low-temperature coal tar and coal shale were investigated using dynamic thermogravimetry. The kinetic characteristics of the process were determined using various methods, including the Ozawa–Flynn-Wall, Friedman, non-parametric kinetics and Šesták–Berggren methods. It is shown that coal shale initiated changes in the kinetic parameters and decomposition rate of the heavy fraction of coal tar. It was found that a 13% content of coal shale in the mixture led to the maximum rate of weight loss of the heavy fraction of coal tar. A hydrodemetallization kinetic model of the mixture of the heavy fraction of low-temperature coal tar and coal shale is proposed. The kinetic parameters of the hydrodemetallization process were determined; in addition, the rate constants at various temperatures were estimated. The study shows that the distribution of trace elements in the hydrogenate from the initial mixture and in the hydrogenate from the solid residue was characterized by relatively low values of reaction rate constants. The maximum microelement distribution rate was achieved in the hydrogenate solid residue. Energy indicators of activation processes indicated that hydrodemetallization at low temperatures is advantageous from an energy point of view.

Kinetics of thermal degradation of polymeric materials is usually studied by weight loss at a constant temperature or during heating. Hence, the activation energy and other kinetic parameters of the thermal destruction process are determined. One of the fastest and most accessible methods for studying the kinetics of these processes is TGA. Weight methods of TGA do not provide an opportunity to judge the proportion of gaseous degradation products. This is especially true for processes associated with the release of hydrogen and other substances with low molecular weights, the accuracy of determining the amount of which by the weight method is low. Meanwhile, the study of the gas evolution process can provide additional information about the kinetics and mechanism of thermal destruction processes. Of great interest is also the joint study of the total weight loss and gas evolution during the polymer heating. Using mass spectrometry, IR spectroscopy combined with thermal analysis (TGA/DSC-IR and TGA/DSC-MS) we have defined product composition and thermal destruction kinetics. As a result of the TGA/DSC-MS study of gaseous products of thermolysis in nitrogen atmosphere, there were found products with 44, 45, 59, 60, 68, and 88 phr. Quite a similar pattern for p-PGFPh:AA copolymers is also observed in TGA/DSC-IR studies: the same products and the same temperature range. However, in contrast to the TGA/DSC-MS study, CO release was also recorded by this method (weak signal). Kinetic characteristics of the processes were determined based on Friedman, Ozawa-Flynn-Wall and modified NPC methods. Obtained values of the activation energy and thermodynamic characteristics make it possible to predict the composition of polymers, which make a significant contribution to the development of theoretical ideas about the features of the physicochemical properties of polymers.

Бас редактор: ЖҰРЫНОВ Мұрат Жұрынұлы, химия ғылымдарының докторы, профессор, ҚР ҰҒА академигі, Қазақстан Республикасы Ұлттық ғылым академиясының президенті, АҚ «Д.В.Сокольский атындағы отын, катализ және электрохимия институтының» бас директоры (

The article is devoted to the study of the influence of external factors on copolymers based on poly(propylene fumarate phthalate) with acrylic acid. In the present work, the effect of low-molecular salts on the swelling rate of the synthesized copolymers was studied. The surface morphology was examined using SEM. The swelling rate of the studied polymers depends on many factors, including the nature of the polymer and the solvent, the presence of electrolytes, changes in pH and ambient temperature, the molecular weight of the polymer, etc. It is assumed that the polymer network of copolymers mainly consists of links of unsaturated polyester resin. The results show that the ratio of monomer units in the copolymer significantly affects the susceptibility of the polymer gel to the presence of low-molecular salts. Changing the properties of the comonomer has been shown to produce hydrogels that can swell or collapse due to changes in ionic strength or the thermodynamic quality of the solution. By varying the ratio of the comonomeric units, the intervals of swelling and contraction of polymer meshes inherent in polyelectrolyte bodies with the same charges were adjusted. It was also found that the polymers under consideration belong to anionic meshes.

The study of the kinetic parameters of copolymers based on polyethylene glycol fumarates, as well as the external and internal effects on them, is essential for production processes at various levels. This will solve a whole range of issues in the field of the shelf life of materials and storage conditions. All these point to the relevance of this research. The authors of the research attempt to test the most common thermogravimetric data processing methods and to improve them in terms of the quality of the predictive capabilities of the resulting regression equation. Both of them are important for the production of initial components and the manufacture of the final product from the studied materials. Therefore, the study and further use of the numerical data of the TG/DTA curves applies to both theoretical and practical branches of science. Thus, summarizing the experimental data on the thermal stability studies, we assume that p-EGF: AA copolymers with compositions of 21.03:78.97 and 68.96:31.04 wt.% have a relatively high degree of resistance to heating. It was found that the calculation by the FR method agreed well with the results of the KAS method. It should be noted that for the p-EGF: AA copolymer (21.03:78.97 wt.%) at heating rates of 5.0, 10.0, 20.0 °С∙min–1, the average activation energy data obtained for two methods increase in the following series:KAS E = 187.34 kJ /mol

The results of analysis of the thermal decomposition kinetics of inclusion complexes of β-cyclodextrin with the alkaloid anabasine at different heating rates are presented. The kinetic characteristics of the processes are determined based on the Friedman, Flynn–Wall–Ozawa and nonparametric kinetics methods.

The encapsulation of the famous alkaloid, anabasine, with β-CD was studied to obtain a more stable and bioavailable inclusion complex. Various in silico and experimental studies of the obtained β-CD-anabasine complex are presented. Firstly, molecular docking studies were conducted against the α, β, and γ cyclodextrins to explore which subclass is the best for encapsulation. The obtained results that pointed at β-cyclodextrin were further confirmed by five MD simulations and MM-PBSA studies. Experimentally, the spectral properties of the anabasine β-cyclodextrin complex were determined by FT-IR, 1H, and 13C-NMR spectroscopic methods. Additionally, the surface morphology of the anabasine β-cyclodextrin was investigated using a scanning electron microscope. Furthermore, the outputs of the thermographic measurements utilizing a differential scanning calorimeter were displayed. The activation energy of the reaction of thermo-oxidative destruction of the clathrate complex was calculated, and the kinetic parameters of the thermal destruction processes were decided using the Freeman–Carroll, Sharpe–Wentworth, Achar, and Coates–Redfern methods. The kinetic parameters of the thermal decomposition of the anabasine β-cyclodextrin were in agreement and verified the reliability of the obtained results. The obtained computational, spectral, morphological, and thermogravimetric results verified the successful formation of the anabasine β-cyclodextrin complex.

The results of the computational and the physicochemical studies of the encapsulation of resveratrol with β-cyclodextrin are presented here. At first, the molecular docking experiments predicted good binding. Several MD simulations and MM-PBSA experiments confirmed the reliable binding, showing optimal kinetics and energy. As an application, resveratrol inclusion complexes with β-cyclodextrin were obtained in an aqueous alcohol medium via microwave treatment. The results of thermographic measurements of the obtained clathrates using a differential scanning calorimeter are presented, and the obtained activation energy was calculated using the Ozawa–Flynn–Wall and Friedman methods, as well as nonparametric kinetics. The effect of complexation on the kinetic parameters of thermal destruction of the β-cyclodextrin–resveratrol inclusion complex was considered. The morphology of the surface of the obtained clathrate complexes was described using a scanning electron microscope. The spectral properties of the inclusion complex were characterized by FT-IR, 1H, and 13С NMR spectroscopic data. The obtained in silico, morphological, thermogravimetric, and spectral results confirmed the formation of the resveratrol–β-cyclodextrin complex. The antioxidant activities of the inclusion complex were determined to be 12.1 μg/mL, compared to 14.3 μg/mL for free resveratrol, indicating an improvement in the bioactivity.

The article presents the results of the synthesis and study of the structure of metal-polymer complexes p-EGM: АА/Ag, p-EGM: АА/Ni, p-EGM:АА/Ag-Ni, p-PGM:АА/Ag, p-PGM:АА/Ni, p-PGM:АА/Ag-Ni based on copolymers of polyethylene(propylene)glycolmaleates with acrylic acid and metals, which have been characterized using microscopy, spectroscopy and thermogravimetry. The antimicrobial activity of a new metal-polymer nanocomposite p-PGM/АА-Ag was studied, which is showing high efficiency against standard strains of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus.

Studies have shown the possibility of synthesizing new polymers based on polypropylene glycol maleate with acrylic acid in the presence of a RAFT agent (2-Cyano-2-propyl dodecyl trithiocarbonate CPDT). The effect of RAFT agent concentration on network density has been shown to be connected with product yield. Herein, the composition of the obtained copolymers was determined using FTIR spectrometry in combination with the chemometric method of partial least squares (or projection to latent structures). To investigate the synthesized hydrogels, the degrees of equilibrium swelling was studied. The resulting objects were characterized by infrared spectroscopy. The surface morphology of the polymers was studied and the pore sizes were estimated using scanning electron microscopy. The structure of the test samples was confirmed by NMR spectroscopy. The thermal stability of crosslinked polymers was determined using thermogravimetry.

This work demonstrates the capability of synthesizing new polymers based on unsaturated polyester and acrylic acid in the presence of a chain-transfer agent in a dioxane solution. The initial unsaturated polyester resin was derived from the polycondensation reaction of alcohol and maleic anhydride. The molecular weight of the polypropylene glycol maleate was determined by gel permeation chromatography. The dependence of the structure, network density and product yield on the concentration of the RAFT agent was proven. It was found that the greater the amount of chain-transfer agent in the monomer mixture, the lower the yield of the crosslinked polymer and the greater the yield of the branched copolymer. The composition of the studied co-polymers was determined by FTIR spectroscopy in conjunction with the chemometric method of partial list squares in the R environment. The synthesized objects were characterized by infrared spectroscopy methods and were approximated by Gaussian contours. The study results show that the RAFT agent concentration, as well as the initial ratio of monomers in the copolymer affects the products yield. The surface topography of the studied copolymers was recorded by scanning electron microscopy. The molecular chain structure of the branched copolymers was confirmed by NMR spectroscopy.

The thermal decomposition of polyethylene glycol fumarate–acrylic acid copolymer is investigated at different rates of heating. It is shown that increasing the rate of heating raises the temperature of the onset of decomposition. The kinetic parameters of decomposition are calculated using the integral Kissinger–Akahira–Sunose procedure. It is found that at different degrees of conversion, the activation energies are very close: E = 205–227 kJ/mol. The effect the composition of the copolymer has on the results from kinetic calculations is shown. The Coates–Redfern approach is used to determine the pre-exponential factor and the model of thermal decomposition. Calculated thermogravimetric curves are constructed and compared to experimental ones.

The present work aimed at encapsulation of fat-soluble vitamin Aevit (vitamins A and E, oil) with β-cyclodextrin. Inclusion complex of vitamins A and E with β-cyclodextrin was prepared in an aqueous alcohol medium by ultrasonic treatment. The surface morphology of the resulting clathrate inclusion complexes was described using a scanning electron microscope. The results of thermographic measurements on a differential scanning calorimeter are presented. The spectral properties of the inclusion complex are characterized by 1H and 13C NMR spectroscopy data. The experimental results confirmed the existence of a complex of inclusion of β-cyclodextrin with vitamin Aevit (2:1). The activation energy of the thermooxidation destruction reaction of the clathrate complex β-cyclodextrin:vitamin Aevit was calculated, kinetic parameters of thermal destruction of clathrate were determined. These parameters were determined based on the Freeman-Carroll, Sharpe-Wentworth, Ahar and Coates-Redfern methods. The use of the above models made it possible to graphically establish the thermodynamic parameters of the thermal decomposition of β-cyclodextrin and its clathrate with vitamin. The data of thermographic measurements on a differential scanning calorimeter showed that the thermal destruction of the Aevite clathrate with β-cyclodextrin begins with the removal of water molecules from the β-cyclodextrin cavity, then the “guest” substance and the cyclic oligosaccharide are destroyed.

Thermogravimetric kinetic investigation of β-cyclodextrin and its inclusion complex with vitamin E has been carried out. The activation energy and pre-exponential factor of their thermal decomposition have been determined based on the kinetic analysis methods known as the Freeman–Carroll, Sharp–Wentworth, Achar and Coats–Redfern ones.