2026

Permanent URI for this communityhttps://crust.ust.edu.ua/handle/123456789/22312

UKR: У даному репозитарії представлені електронні версії статей, автори яких є членами співтовариства університету. Зі статтями авторів, що не працюють в УДУНТ, можна ознайомитися на сайті журналу "Питання хімії та хімічної технології".
ENG: This repository contains e-articles whose authors are members of the community of the university. Articles of authors who are not USUST employees are available online at the website of the journal "Voprosy Khimii i Khimicheskoi Tekhnologii / Issues of Chemistry and Chemical Technology".

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Searching for the Chemical Component of the Starch Dehydration Process
(Ukrainian State University of Science and Technologies, 2026) Nikolenko, Mykola V.; Sakhno, Yu.; Myrhorodska-Terentieva, V. D.; Hrechka, Dmytro S.; Vashkevich, Olena Yu.
ENG: As is well known, the first stage of starch heat treatment is the dehydration process, which proceeds in a kinetic mode with a relatively high activation energy value of 40–60 kJ/mol. The reason for this may be both the energy-consuming process of hydrogen bond destruction in starch and the chemical reaction between the OH groups of polycarbohydrates with the formation of ester bonds. The aim of the study was to find evidence of the formation of such bonds during the heat treatment of corn starch. The studies were performed by FTIR spectroscopy in the temperature range of 60–2550C at a heating rate of 40C/min. It was found that the number of OH groups of polycarbohydrates gradually decreases during starch heating, while the water content and ether-bond signals, on the contrary, increase. An increase in water concentration was observed when starch was heated to a temperature of 1300C. It was concluded that these trends are well explained by the course of the condensation reaction between the OH groups of amylose and amylopectin molecules. For the first time, it was found that during prolonged drying of starch in a vacuum, even at a temperature of 500C, the crosslinking of polycarbohydrate molecules occurs due to the formation of ester bonds. It is noteworthy that such crosslinking occurs without the use of chemical reagents, but only by shifting the equilibrium of the condensation reaction as a result of the continuous removal of water from starch.
Influence of Solid-State Polycondensation Conditions on the Intrinsic Viscosity of Recycled Poly(Ethylene Terephthalatе)
(Ukrainian State University of Science and Technologies, 2026) Chervakov, Denys O.; Ved, Viktor V.; Fedan, V. V.; Sukhyy, Kostyantyn M.; Chervakov, Oleh V.
ENG: The study investigates the influence of solid-state polycondensation (SSP) conditions on the change in intrinsic viscosity (IV) of recycled poly(ethylene terephthalate) (PET) processed via a bottle-to-bottle technology. Experimental work was carried out within the temperature range of 110–1600C while varying the duration of SSP. It was found that during SSP at 110–1300C, the intrinsic viscosity of PET-BTB increased by 23–34%, whereas the melt flow index (MFI) decreased by up to 54%, indicating a nonlinear relationship between IV and MFI. A mathematical model was proposed to predict IV as a function of temperature, SSP duration, and MFI value. Validation of the model revealed a deviation not exceeding 6%, which confirms its high practical reliability. The proposed approach enables a reduction in the scope of experimental work required for optimizing SSP conditions of recycled PET and assessing its recyclability toward products with the desired level of physical and mechanical properties.
Interaction of N-Alkoxy-N-Chloro-N’-Arylureas With Trialkyl Phosphites as a Route to Dialkyl N-Alkoxy-N-(N’-Arylcarbamoyl)Phosphoramidates. Products Structur
(Ukrainian State University of Science and Technologies, 2026) Shtamburg, Vasiliy G.; Klots, E. A.; Anishchenko, A. A.; Shtamburg, V. V.; Shishkina, S. V.; Mazepa, A. V.; Kravchenko, S. V.
ENG: It is shown that the interaction of N-alkoxy-N-chloro-N’-arylureas with trialkyl phosphites in diethyl ether at room temperature yields dialkyl N-alkoxy-N-(N’-arylcarbamoyl)phosphoramidates. The structures of the dialkyl N-alkoxy-N-(N’-arylcarbamoyl)phosphoramidates were finally confirmed by a single-crystal X-raydiffraction study. The structural peculiarities of dialkyl N-alkoxy-N-(N’-arylcarbamoyl)phosphoramidates are discussed. The single-crystal X-ray diffraction study of dimethyl N-methoxy-N-(N’-4-nitrophenylcarbamoyl)phosphoramidate, dimethyl N-benzyloxy-N-(N’-4-nitrophenylcarbamoyl)phosphoramidate, and diethyl N-methoxy-N-(N’-4-chlorophenylcarbamoyl)phosphoramidate revealed the planar configuration of the N(OR) nitrogen atom. The strong conjugation of the lone pair on the N(OR) nitrogen atom with the π-systems of the P=O and C=O double bonds leads to a planar configuration of the N(OR) nitrogen. Differences in the N–C(=O) carbamoyl bond are observed in dialkyl N-alkoxy-N-(N’-arylcarbamoyl)phosphoramidates. The N(Ar)–C(O) bond is shorter than the N(OR)–C(O) bond; a significant length difference of the N–C(=O) carbamoyl bonds is observed. This phenomenon may be caused by the fact that the conjugation of the lone pair on the N(OR) nitrogen atom with the carbamoyl C=O group is weaker than the conjugation of the lone pair on the N(Ar) nitrogen atom with the same carbamoyl C=O group. In all cases, the N-aryl substituent is almost coplanar with the carbamoyl group.
Elastomeric Compositions With Rice Husk-Based Bio-Ingredients
(Ukrainian State University of Science and Technologies, 2026) Sokolova, Lina О.; Ovcharov, Valery І.; Hrydnieva, Тatyana V.; Тertishniy, O.A.; Тyshchenko, V.O.
ENG: Іn the context of the global growth of green chemistry and the circular economy, the use of crushed rice husk (CRH) as a bio-ingredient in elastomeric compositions offers an environmentally sustainable alternative. It has been found that modification of the husk with surfactants, in particular the cationic quaternary ammonium salt (QAS-4) synthesized from sugar-industry biowaste, significantly improves the interaction between the husk and the rubber matrix, increases the degree of crosslinking, and enhances the physical and mechanical properties of the rubbers, such as tear and heat resistance. Experimental results showed that compositions with CRH modified with QAS-4 demonstrate advantages in processability, including preservation of the rubber compound’s plasticity and acceleration of sulfur vulcanization, as well as improved performance characteristics of industrial rubbers compared with traditional fillers. The use of CRH, especially in a modified form, is a promising direction for creating environmentally friendly and costeffective elastomeric compositions.