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Development and research of formulations for the production of functional ceramic materials

https://doi.org/10.58224/2619-0575-2025-8-4-1
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Abstract
The authors investigated a mixture for producing Ceram Bond ceramic adhesive (Bredent, Germany). The microstructure of the initial powder and the resulting coating after sintering at 980°C were analyzed. The resulting compositions are easily manipulated under industrial conditions and possess optimal processing properties.
Objectives: Research and development of new, effective functional ceramic coating compositions for dental prosthetics that meet high quality and durability requirements.
Methods. Analytical and experimental chemistry methods were used, as well as modern instruments and equipment. The chemical and phase composition was studied using an X-ray fluorescence spectrometer. The elemental composition of the experimental samples was determined using an energy dispersive attachment to a scanning electron microscope. The granulometric composition of the masses was determined using laser diffractometry. The microstructure of the powder and ceramic adhesive was examined using a scanning electron microscope. The structure of the coatings was recorded using an optical microscope. The preparation of the ceramic adhesive was carried out by wet grinding. The determination of water absorption, open porosity and apparent density was carried out using a vacuum chamber connected to a vacuum pump. The calculation of these parameters was carried out according to classical formulas.
Results. The analysis of the main physico-mechanical characteristics of a sample of a mixture in a paste-like state of the Ceram Bond brand, the Bredent trademark (Germany) is carried out. The compositions of experimental samples have been developed, their physico-mechanical properties have been determined, and the advantages and disadvantages of introducing flat glass and fused quartz into the combat have been identified. It has been established that coatings based on Ceram Bond adhesive are characterized by the presence of a large number of microcracks, and experimental formulations differ in a small number or completely absence of microcracks, which indicates its higher quality.
Conclusions. As a result of the work carried out, a mixture for the production of ceramic adhesive of the Ceram Bond brand of the Bredent trademark (Germany) was investigated. Experimental formulations have been developed for the production of ceramic adhesives based on fused quartz and tempered flat glass. The microstructure of the initial powder and the coating based on it after sintering at a temperature of 980℃ has been studied. It has been established that coatings based on Ceram Bond adhesive are characterized by the presence of a large number of microcracks, and the developed formulations differ in a small number or complete absence of microcracks, which indicates their higher quality.
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Comparison of modifying effect of wollastonite in polyvinylchloride and epoxy composite materials

https://doi.org/10.58224/2619-0575-2025-8-4-2
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Abstract
To investigate the grain-size and phase compositions and properties of natural and synthetic wollastonite fillers and to establish the nature of their modifying effect in polymer composite materials using the example of polyvinyl chloride thermoplastic and epoxy resin thermoset.
Methods. X-ray quantitative phase analysis was used to study the filler samples, and porosity was determined using mercury porosimetry and gas absorption. The particle size of wollastonite was determined by laser diffraction. The thermal stability of the filled composites was evaluated on a derivative thermogravimetric analyser, and the thermal stability of polyvinyl chloride materials was evaluated using the Congo red method. Dynamic mechanical analysis was performed on a DMA 242 Netzsch device.
Results. The particle size distribution and phase composition of natural and synthetic calcium silicate samples, their porosity and pH of aqueous extract were studied. The influence of wollastonite properties on the viscosity of the obtained polymer-filler mixtures, the thermal stability and wear resistance of the filled composites, as well as on the tensile strength and relative elongation of polyvinyl chloride compositions was established.
Conclusions. Studied calcium silicates have proven effective for both epoxy and polyvinyl chloride materials. Despite the similarity in phase composition and acid-base characteristics of the surface, natural and synthetic wollastonite differ in particle size distribution and porosity. Natural filler is more promising for creating heat-resistant polyvinyl chloride compositions and wear-resistant epoxy compositions, while synthetic wollastonite based on rice husks provides an increase in the dynamic modulus and glass transition temperature of both types of polymers. Studies have shown that the modifying effect of the studied fillers is more prominent in epoxy polymers due to their influence on the formation of the polymer matrix cross-linked structure.
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Study of the cerebroprotective effect of a new derivative of hydroxybenzoic acid – the dikali salt N–(3-hydroxybenzoyl)taurine in various disorders of cerebral circulation

https://doi.org/10.58224/2619-0575-2025-8-4-3
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Abstract
The 21st century is not only a time of progress in innovative technologies and artificial intelligence, but also a time of global downgrade and early development of serious health disorders, especially oncological and cardiovascular diseases. Currently, various cerebrovascular disorders have become widespread, which are the main limitation factors in rational therapy. This is due to the complications of primary diagnosis of the disease and its confirmation, as well as the problems in the application of early neuroprotection and rehabilitation. The aim of the study. The research of new compound’s neuroprotective properties: the dipotassium salt of N-(3-hydroxybenzoyl)taurine, which is a derivate of hydroxybenzoic acid, by the different types of vascular (blood circulation) disorders in the brain. Materials and methods. The examination of the dipotassium salt of N-(3-hydroxybenzoyl)taurine, as a derivate of hydroxybenzoic acid. Establishing the neurological status using the Combs & D`Alecy scale and the Gracia scale. Results. The research results let to suggest the cerebroprotective properties of a new hydroxybenzoic acid derivate, which demonstrates potential comparable to Citicoline, Nicergoline, and Acetylsalicylic acid in decrease the damage of the neuropsychiatric consequences of ischemic injury. The examine compound, like these other drugs, exhibits properties aimed at stabilizing cerebral circulation and reducing the manifestations of endothelial dysfunction. Conclusions. According to study findings the dipotassium salt of N-(3-hydroxybenzoyl)taurine exhibits cerebroprotective effects in various cerebrovascular disorders.
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Quantum chemical modeling оf aqueous mustard gas solutions

https://doi.org/10.58224/2619-0575-2025-8-4-4
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Abstract
Objective: to conduct quantum chemical modeling of a sulfur mustard molecule in an aqueous medium in the built–in parameter mode and in the mode of added molecules. After optimization by thermodynamic parameters, to study possible molecular and structural changes of mustard gas in the composition of the medium.
Methods. The Gaussian software package with the GaussView visualizer was used to construct and visualize the structure of the sulfur mustard molecule and its interaction with the aquatic environment. To carry out the calculation (calculation tipe FREQ), the standard Gaussian ab initio – Hartley-Fock (RHF) and post-Hartley-Fock (MP2) methods were chosen, which alternated with calculations based on the theory of the density function (DFT): B3LYP and B3LYP-FC. The semiempirical RPM6 method is used as a boundary factor.
Results. It is shown that only a comprehensive analysis of the state of the molecule makes it possible to identify the specific contribution of each type of interaction to the structure and properties of the molecule. In an aqueous environment, the mustard gas molecule has a high stability potential, but exposure to a real molecular environment leads to a change in polarizability, atomic charge, and dipole moment vector, and in the excited state of the molecule, one of the C1-Cl1 bonds is maximally activated, practically doubling its length.
Conclusions. Despite the very poor solubility of mustard gas in water, its intermolecular interaction with the medium leads to a redistribution of energy characteristics and the formation of a nonequilibrium polarizable state of the mustard molecule in the structure of the aquacomplex, possible further destruction with the formation of toxic products, including onium cations. Further development of the obtained results will make it possible to justify the choice of conditions for targeted activation of the mustard gas molecule for detoxification in aqueous media and body fluids.
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Adsorption of methylene blue by activated pyrolysis products of sunflower seed husks

https://doi.org/10.58224/2619-0575-2025-8-3-1
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Abstract
In the context of the global environmental crisis caused by the rapid growth of industrial and household waste, the search for effective methods of their recycling is becoming a key task of sustainable development. Traditional disposal methods, such as burial or incineration, not only require significant resources, but also lead to atmospheric pollution with negatively biologically active gases. In this context, pyrolysis of carbon-containing waste represents a promising alternative combining environmental safety and economic feasibility. Unlike combustion, pyrolysis takes place in an environment with a limited oxygen content, which minimizes CO and CO2 emissions, and also allows for the production of valuable secondary products — pyrolysis gases, liquid and solid carbon materials. The latter are suitable for use as adsorbents. Activation of pyrolysis products by chemical reagents (alkalis, acids, or steam) is used to increase the adsorption capacity, which significantly increases their porosity and adsorption capacity. In this work, the adsorption properties of sunflower husk pyrolysis products activated with an aqueous 2 M solution of potassium hydroxide (KL-21(A)), sunflower husk pyrolysis products combined with bentonite clay (KL-21(A)) and pyrolysis products of crushed worn car tires (KR-21(A)) were determined. Their effectiveness in terms of adsorption of methylene blue (MG), a model cationic dye widely used in assessing the absorption capacity of adsorbents, has been studied by spectrophotometric method. Kinetic dependences of adsorption have been established, and the maximum adsorption capacities of experimental materials have been determined depending on MG concentration. The results of experimental studies allow us to conclude that the activation of pyrolysis products of crop and communal waste with potassium hydroxide improves the adsorption characteristics of the developed material.
Objectives: to identify the adsorption properties of pyrolysis products of sunflower seed husk KL-21(A) activated with an aqueous 2 M solution of potassium hydroxide, pyrolysis products of sunflower seed husk combined with bentonite clay KL-21(A) and pyrolysis products of worn-out automobile tires KR-21(A).
Methods. A Nabi MicroDigital spectrophotometer (South Korea), laboratory instruments and reagents were used to study the adsorption properties by the spectrophotometric method.
Results. Graphical dependences of the absorption capacity on the duration and rate of adsorption are revealed, and adsorption isotherms are constructed and analyzed.
Conclusions. An adsorption-active material based on pyrolysis products of sunflower seed husks and pyrolysis products of worn-out automobile tires was obtained. The adsorption capacity of CL-21(A) samples was 474 mg/g, CLG-21(A) – 131 mg/g, and KR-21(A) – 351 mg/g. The obtained isotherms are determined by the Langmuir model.
It was found that the adsorption equilibrium occurs after 6 hours in KL-21(A) and a day later in KL-21(A) and KR-21(A).
It was found that the highest rate of adsorption is characteristic of the KL-21(A) sample and amounted to 0.00094 mmol/min or 0.300 mg/min in the first 15 minutes of exposure.
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Colloidal protection of magnetite hydrosols with polysaccharides

https://doi.org/10.58224/2619-0575-2025-8-3-2
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Abstract
This article investigates the stabilization of aqueous dispersions of magnetic Fe₃O₄ nanoparticles using polysaccharide stabilizers. The effect of electrolyte coagulants and polysaccharide stabilizers on the stability of magnetite hydrosols and their stability at physiological pH with and without the addition of polysaccharides is stud-ied. The results demonstrate the effectiveness of nonionic polysaccharides, such as hydroxypropyl methylcellulose and hydroxyethylcellulose, in stabilizing magnetic nanoparticles from electrolyte coagulation and over time, which is important for their application in medicine.
Objectives. To obtain and characterize magnetite hydrosols and to study their stabilization with polysaccharides over time and with the addition of non-indifferent and indifferent electrolytes.
Methods. Hydrosol coagulation was studied photometrically. The size of hydrosol nanoparticles was determined using dynamic light scattering.
Results. Nonionic polysaccharides, such as hydroxyethyl cellulose and hydroxypropyl methylcellulose, are promising for stabilizing aqueous dispersions (hydrosols) of Fe3O4 magnetic nanoparticles.
Conclusions. The coagulation threshold of magnetite hydrosol with a non-differentiated electrolyte, sodium hy-droxide, is 20,5 times lower than the coagulation threshold of magnetite hydrosol with an indifferent electrolyte, sodium chloride. Hydroxyethyl cellulose and hydroxypropyl methylcellulose exhibited the greatest protection of magnetite hydrosol from coagulation with sodium chloride. Hydroxypropyl methylcellulose exhibited the greatest protection of magnetite hydrosol from coagulation with sodium hydroxide. Sols containing hydroxypropyl methyl-cellulose exhibit the greatest stability over time at pH 7.4 (the pH of blood), created by the addition of a phosphate-buffered saline mixture.
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Adsorption of Acetone on HNO3-Treated AG-3 Activated Carbon: Performance and Kinetic Study

https://doi.org/10.58224/2619-0575-2025-8-2-1
Abstract
The study focuses on enhancing the adsorption of acetone, a prevalent oxygenated volatile organic compound (VOC), using HNO3-modified AG-3 activated carbon (AC) to mitigate its environmental and health impacts. It aims to optimize HNO3 modification of AG-3 AC, targeting enhanced acetone adsorption capacity and improved kinetics.
Methods: In this work, commercial AG-3 was treated with 2 M, 4, M and 6 M HNO3 solutions through reflux heating at 100 °C, followed by washing and drying. Adsorption experiments were conducted using gravimetric analysis at 25 °C and 1 atm, with kinetic data fitted to pseudo-first-order, pseudo-second-order, Elovich, and Mor-ris-Weber models. The modified ACs were evaluated for their specific adsorption capacities and time-dependent adsorption behaviors.
Results: Results showed that HNO3 treatment enhanced acetone adsorption, with the 2 M HNO3-treated AC (HAC-2) exhibited the highest capacity of 0.2951 g/g, a 15 % improvement over unmodified AG-3 (0.2570). Kinetic studies revealed that the pseudo-second-order kinetic model best described the adsorption process, indicating chemisorption as the primary mechanism. As concentration of HNO3 increased (4 M and 6 M), it led to reduced adsorption capacity compared to HAC-2, suggesting excessive oxidation may damage the carbon structure.
Conclusions: The study concludes that the optimal HNO3 concentration for enhancing acetone adsorption on G-3 AC lies around 2 M. This approach highlights the potential of HNO3-modified AG-3 as an effective adsorbent for acetone remediation in adsorption application.
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A set of possible approximative methods for efficiently recalculating the contribution of coulomb integrals to the elements of the single-electron hamiltonian at SCF iterations to dramatically speed up extremely resource-intensive DFT calculations of giant biomolecules

https://doi.org/10.58224/2619-0575-2025-8-3-3
Abstract
The investigation aims to identify potential approximative methodologies for expediting repeated calculations of Coulomb integral contributions to single-electron Hamiltonian elements during self-consistent field (SCF) iterations, thereby dramatically accelerating computationally intensive density functional theory (DFT) analyses of massive biomolecular structures. The research addressed several challenges: a) evaluating semi-empirical approaches for quantum chemical examination of enormous molecular systems; b) exploring how numerous distant molecular fragments could facilitate faster computation of Coulomb interaction contributions; c) examining contemporary approaches to fixed-geometry single-point molecular calculations; d) developing innovative methodologies for accelerated Coulomb integral contribution computation in DFT analyses of substantial bi-omolecular entities.
We present a novel suite of approximation techniques designed to substantially expedite calculations of Cou-lomb integral contributions to one-electron Hamiltonian elements in conventional DFT methodologies during SCF iterations-typically the rate-limiting phase of these essential yet computationally demanding calculations for exten-sive biomolecular systems, including thousands of docking complexes comprising thousands of atoms.
Our integrated approach features rapid and precise approximation of contribution modifications across innu-merable 4-center Coulomb integrals between successive SCF iterations through auxiliary density function-mediated transformation into linear combinations of 3-center integrals, subsequently converted to combinations of 2-center integrals. Contribution variations from non-multipole short-range components of these 2-center integrals are swiftly determined by modifying pre-computed spline contributions based on inter-atomic separations. The re-maining multipole-based long-range contributions undergo rapid computation for expansive molecular systems using a fast multipole method (FMM) framework, which strategically partitions extensive spatial domains into hi-erarchical regions (a technique originally pioneered for galactic dynamics simulations).
Each SCF iteration employs sophisticated screening to identify exclusively non-negligible integral combina-tions, particularly accounting for the progressively diminishing density matrix increments characteristic of con-verging SCF processes. The framework accommodates the unique characteristics of specific massive molecular systems or extensive collections thereof, such as thousands of docking arrangements between substantial protein structures and diverse small organic ligand molecules.
All bimolecular components-including approximations of two-center basis function overlaps via linear combi-nations of single-center auxiliary density functions-undergo efficient computation utilizing specialized database-stored inter-nuclear distance splines. For novel basis sets, the reference database can be promptly augmented through decomposition into universal exponential components with corresponding database enrichment.
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Synthesis of sulfur-containing precursor of targeted lipoconjugates

https://doi.org/10.58224/2619-0575-2025-8-3-4
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Abstract
Objectives: To search for and develop a method for synthesizing sulfur-containing lipids based on 1,2-di-O-tetradecyl-rac-glycerol.
Methods. Separation and purification of the obtained compounds were accomplished by column chromatography on silica gel and extraction. A combination of physicochemical analytical methods, including NMR-spectroscopy and mass-spectrometry, was used to confirm the structures of the obtained compounds.
Results. A new method for synthesizing sulfur-containing precursors for targeted lipoconjugates has been developed. 1,2-di-O-tetradecyl-rac-glycerol with a tetraethylene glycol spacer was used as the hydrophobic domain. Divinyl sulfone was attached to the terminal amino group under basic conditions. However, proton signals from the dioxothiomorphonyl group were detected in the NMR spectra of the resulting compound, confirming the cyclization of the vinylsulfone group with primary amines. This problem can be solved by replacing divinyl sulfone with its analog with an ethylene glycol spacer, bis-vinylsulfone, and alkylating the primary amino group of the tetraethylene glycol spacer, since the formation of the dioxothiomorphonyl group is excluded from secondary amines.
Conclusions. The interaction of divinyl sulfone with the primary amino group of a tetraethyleneglycol-containing lipid based on 1,2-di-O-tetradecyl-rac-glycerol was investigated. The resulting addition reaction product was further used to create CL and study the delivery of NA to target cells. The search for optimal synthesis conditions for producing vinyl sulfone-containing precursors of the targeted lipoconjugates will also continue.
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Bentonite from the Nalchik deposit and the possibilities of its use as a cationic adsorbent

https://doi.org/10.58224/2619-0575-2025-8-2-2
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Abstract
Chemical, mineralogical, granulometric and structural-morphological characteristics of bentonite clays of the Nalchik deposit have been established. The elemental composition contains B (trace amounts), Al, Si, K, Ca, Ti, Fe. It has been revealed that the mineralogical composition of the studied clay is complex of montmorillonite, clinoptilolite and low-temperature trigonal quartz. The montmorillonite content is 53.0 ± 1.1 wt.%. The maximum particle size is 198.7-210.1 μm, the proportion of such particles is 0.69 wt.%. The minimum particle size is 0.6-0.9 μm, the proportion of such particles is 1.22 wt.%. According to the results of differential thermal analysis, 4 endoeffects were recorded, the total mass loss on sample calcination was 16.5%, taking into account the loss of free water - 9.5 wt.%. The adsorption characteristics of the analyzed bentonite were studied using “model” pollutants – nickel (II) cations and methylene blue dye. It was found that the adsorption isotherm of nickel (II) ions belongs to class L type 3, and the adsorption isotherm of methylene blue belongs to class L type 2 according to the Gils classification. The results of the study showed that bentonite clay from the Nalchik deposit is capable of purifying wastewater to the maximum permissible concentration of cationic pollutants.
Objectives: to investigate the material composition and adsorption properties of bentonite clay from the Nalchik deposit.
Methods. To determine the elemental, phase and granulometric composition, the following equipment was used: transmission electron microscope JEM-2100 (Jeol, Japan), diffractometer Ultima IV (Rigaku, Japan), combined analyzer TG/DTG/DTA SDT Q600 (TA Instruments, Inc., USA), particle size analyzer Microtrac S3500 (USA), as well as laboratory instruments and reagents.
Results. The mineralogical composition of the clay sample from the Nalchik deposit was established; the mass content of montmorillonite was determined. The granulometric composition was studied. The adsorption processes of the clay sample in relation to the organic dye methylene blue and nickel (II) ions were investigated.
Conclusions. The mineralogical composition of the clay sample from the Nalchik deposit was determined: montmorillonite, clinoptilolite and low-temperature trigonal quartz. The montmorillonite content is 53.0 ± 1.1 wt.%. The maximum particle size of the fraction in the studied clay sample is 198.7-210.1 μm, the proportion of such particles is 0.69 wt.%. The minimum particle size of the fraction is 0.6-0.9 μm, the proportion of particles is 1.22 wt.%. The adsorption processes of the clay sample in relation to the organic dye methylene blue and nickel (II) ions were studied. It was shown that the clay of the Nalchik deposit is capable of purifying wastewater from the specified cationic pollutants to the regulatory requirements.
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