By means of kinetic simulation, we established how the cure rate of an acrylic adhesive composition, poly(methyl methacrylate) macroinitiator + methyl methacrylate, was related with the composition of the macroinitiator obtained by radical-coordination polymerization in the presence of a benzoyl peroxide + titanocene dichloride catalytic system and to its synthesis conditions. The cure rate of the adhesive composition was found to increase with an increase in the content of coordination active sites in the macroinitiator, i.e., upon a temperature rise and an increase in the ratio of the initial titanocene dichloride concentration to the initial benzoyl peroxide concentration in the synthesis of macroinitiator. An increase in the cure temperature of the adhesive composition also led to an increase in the cure rate. It is shown that the macroinitiator composition and the cure rate of the adhesive composition can be controlled more precisely when the macroinitiator is obtained in the presence of the catalytic system benzoyl peroxide + titanocene dichloride, rather than benzoyl peroxide + ferrocene, since the macroinitiator composition is less susceptible to the initial concentration of titanocene dichloride compared to the initial concentration of ferrocene.

Chromatography-mass spectrometry of samples representing the interaction products of ferrocene, radical initiator and monomer taken in the molar ratio of 1 : 2 : 10 in toluene solution was used for experimental detection of products indicating the structure and mechanism of formation of metal complex active centers of radical-coordination polymerization. Structures similar to those proposed by the quantum-chemical modeling were demonstrated to be formed with the participation of secondary radicals.

При описании полицентровой ионно-координационной полимеризации изопрена на каталитической системе GdCl3 × n(i-C3Н7OH)‒Al(i-C4H9)3 решена обратная кинетическая задача для схемы процесса с медленным инициированием. Задачу определения числа активных центров полимеризации решали путем деконволюции экспериментальных ММР суперпозицией распределений Флори. Найдено, что в полимеризации участвует четыре типа активных центров, кинетическое различие которых в процессе формирования фракций полимера с характерными для них средними молекулярными массами и наиболее вероятным ММР обусловлено их различием в концентрациях предреакционных каталитических центров и константах скоростей протекающих на них реакций. Для каждого типа активных центров определены парциальные конверсии расходования мономера, константы скоростей инициирования, роста цепей и передачи на мономер.

A kinetic model of the curing of methyl methacrylate adhesive (including nanocomposite methyl methacrylate adhesive) in the presence of the initiating systems "aryl peroxide + zirconocene dichloride" and "aryl hydroperoxide + zirconocene dichloride" is made. Computational experiments have been carried out which demonstrate the relationship of the curing rate with the curing temperature in the range of 323-343 K and with the ratio of the initial concentration of zirconocene dichloride to the initial concentration of the initiator [Mc](0)/[I](0) for the following initiators: benzoyl peroxide (PB), ethylbenzene hydroperoxide (HPEB), and ethylbenzene hydroperoxide adduct with cadmium 2-ethyl hexanoate [HPEBCd(EH)(2)]. It is shown that in order to increase the curing rate of the adhesive, curing should be carried out at a higher temperature (343 K) and at a higher value of the ratio [Mc](0)/[I](0) = 10 in the presence of the most rapidly decomposing initiator HPEBCd(EH)(2). To increase the weight-average molecular weight of poly(methyl methacrylate), the proportion of syndiotactic triads in its composition, and consequently, to improve the adhesion strength and heat resistance of the adhesive joint, the curing of the adhesive must be carried out at the reduced temperature (323 K) and the reduced ratio of the [Mc](0)/[I](0) = 0.1 in the presence of the least rapidly decomposing initiator HPEB.

Spectrophotometry is used to determine constants of stability for coordination compounds of apple pectin with indole and L-tyrosine—structural analogs of aromatic amino acids (tryptophan and phenylalanine). It is found that the presence of phenolate oxygen in tyrosine favors bonding to pectin and is attributed to this species’ participation in the forming of H bonds with the carbonyl functional group of the polysaccharide, which ensures better stability of the pectin–tyrosine complex than that of a pectin–phenylalanine system. It is shown that the key contribution to the stability of pectin complex comes from the indole moiety of tryptophan. Based on analysis of thermodynamic characteristics, it is shown that the formation of 1 : 1 molecular complexes for pectin–indole and pectin–tyrosine systems is governed only by the enthalpy component (∆H0 < 0, ∆S0 < 0). The thermal properties of modified pectins are determined.

In the description of multicenter ion-coordination polymerization of isoprene on the catalytic system GdCl3· n(i-C3Н7OH)‒Al(i-C4H9)3 the inverse kinetic task for the scheme of a process with slow initiation has been solved. The task of determining the number of active centers of polymerization was solved by deconvolution of experimental MWDs through superposition of Flory distributions. It has been shown that four types of active centers participate in polymerization, the kinetic difference of which in the process of formation of polymer fractions with their characteristic average molecular weights and the most probable MWD, is associated with their difference in the concentrations of pre-reaction catalytic centers and the rate constants of reactions occurring on them. For each type of active centers, partial conversions of monomer consumption and rate constants of initiation, chain propagation, and chain transfer to the monomer are determined.

The interaction of pectin and arabinogalactan macromolecules in aqueous solutions has been studied. It is shown that polymer complexes are formed due to hydrogen bonding between macromolecules. Crosslinking of the polymer complex by Са2+ ions leads to the formation of hydrogels whose properties are considerably determined by the content of arabinogalactan. At low concentrations of Са2+ ions (from 0.05 to 0.15 wt

The formation of polymer–colloid complexes by the interaction of N , N '-diallyl- N , N '-dimethylammonium chloride–sulfur dioxide copolymers of various molecular weight and sodium dodecyl sulfate is studied. The complexes are characterized by turbidimetric titration and laser light diffraction/scattering. The average particle size of polymer–colloid complexes varies in the range of 150‒200 nm depending on the composition of the reaction mixture and the molecular weight of the polyelectrolyte. The critical aggregation concentrations of sodium dodecyl sulfate in the presence of various molecular weight copolymers are determined. It is shown that the molecular weight of the polycation strongly affects boundaries of the region, in which the phase of polymer–colloid complexes appears, and the sizes of their particles. The ability of complex particles to solubilize molecules of substances poorly soluble in water is evaluated.

A theoretical analysis of wave motions that arise in the ocean under the action of traveling disturbances of atmospheric pressure is presented. Formulas for a fixed-depth ocean have been obtained to describe the manifestations of traveling disturbances of atmospheric pressure in bottom pressure variations. Formulas have been obtained for estimating the amplitude of free gravity waves generated in the ocean by a traveling atmospheric disturbance in the region of a sharp change in depth. Data from IRIS ground-based barographs and DART (Deep-ocean Assessment and Reporting of Tsunami) stations recording wave disturbances in the atmosphere and ocean caused by the explosive eruption of the Hunga Tonga–Hunga Ha’apai volcano on January 15, 2022 have been used to study the atmospheric Lamb wave manifestations in bottom pressure variations. A Lamb wave was shown to be manifested in bottom pressure variations with amplification and identical waveforms recorded by ground-based barographs and bottom pressure sensors. A Lamb wave with an amplitude of 500 Pa can excite surface gravity waves with an amplitude of 0.5 m in the region of a deepwater trench.

Preparation of stable hydrogels using physically (electrostatically) interacting charge-complementary polyelectrolyte chains seems to be more attractive from a practical point of view than the use of organic crosslinking agents. In this work natural polyelectrolytes-chitosan and pectin-were used, due to their biocompatibility and biodegradability. The biodegradability of hydrogels is confirmed by experiments with hyaluronidase as an enzyme. It has been shown that the use of pectins with different molecular weights makes it possible to prepare hydrogels with different rheological characteristics and swelling kinetics. These polyelectrolyte hydrogels loaded with cytostatic cisplatin as a model drug provide an opportunity for its prolonged release, which is important for therapy. The drug release is regulated to a certain extent by the choice of hydrogel composition. The developed systems can potentially improve the effects of cancer treatment due to the prolonged release of cytostatic cisplatin.

The eruption of the Hunga Tonga–Hunga Ha’apai volcano on 15 January 2022 was the first powerful explosive eruption in history to be recorded with high quality by a wide range of geophysical equipment. The atmospheric Lamb wave caused by the explosion repeatedly circled the Earth and served as one of the reasons for the formation of tsunami waves. In this paper, the Lamb wave manifestations are analyzed in the recordings of tsunamimeters, i.e., in data from DONET and DART pressure sensors located in the area of the Japanese Islands. The work is aimed at studying the physics of the formation of pressure variations at the ocean floor in order to develop a method for isolating free gravity waves in records obtained by bottom pressure sensors. Within the framework of shallow water theory, an analysis of the response of the water layer to the atmospheric Lamb wave was performed. This response combines a forced perturbation, the amplitude of which depends on the depth of the ocean, and free gravity waves arising as a result of the restructuring of the forced perturbation on the submarine slopes. Analytical formulas are given for the amplitude and energy of the forced perturbation and free waves arising at the depth jump. With the aid of numerical simulation, the finite length of a slope was revealed to significantly affect the parameters of free waves when exceeding 50 km. The analysis of in situ data (DONET, DART) confirms the validity of theoretical concepts presented in the work. In particular, it is shown that variations of bottom pressure in the deep ocean exceed the amplitude of atmospheric pressure fluctuations in the Lamb wave.

Reliable NMR determination of the stereoisomeric composition of polyisoprene obtained in the presence of a catalyst based on a solvation complex of gadolinium chloride with isopropanol, activated with triisobutylaluminum, is possible only after thorough removal of traces of gadolinium compounds, which are strong relaxants in magnetic resonance imaging. In determination of the stereoisomeric composition of polyisoprene by Fourier IR spectroscopy, more reliable results are reached when plotting a separate baseline for each absorption band.

The thermodynamic and structural study of the complex formation of apple pectin with structural analogs of histidine (imidazole and its methyl ester) was carried out using spectral methods. The composition, stability constants of the complexes, and standard thermodynamic characteristics (ΔG°, ΔH°, and ΔS°) of the complex formation process were determined. The dominating contribution of the imidazole fragment of the amino acid to the stability of the pectin-histidine complex is shown. The esterification of the carboxyl group of histidine and its conversion into methyl ester influence only slightly the efficiency of complex formation with pectin, leading to a slight increase in binding.

The interaction of iodine with low-methoxylated apple pectin (esterification degree 10

Lanthanide catalysts are used in the industrial production of stereoregular rubbers. It is believed that the activity of solvate complexes of lanthanide chlorides increases with decreasing size of their particles and increasing content of the solvating ligand. The kinetics of isoprene polymerization catalyzed by the isopropanol solvates of gadolinium chloride GdCl 3 · n ( i -PrOH), which were obtained by various methods (conventional mechanical stirring, hydrodynamic exposure, ultrasonic irradiation), was studied. A correlation between the particle size and composition of the solvate complex and the activity of the catalyst was found whatever the method the solvate complex was obtained. At the same time, the resulting data show that, at comparable particle size and composition of the complex, its activity in the polymerization of isoprene nevertheless depends on the method of synthesis. It was shown that the gadolinium catalysts exhibit the highest activity in isoprene polymerization, when the solvate complexes are subjected to hydrodynamic treatment after preliminary solvation for 4–8 h.

Исследовано образование полимер-коллоидных комплексов при взаимодействии сополимеров N,N'-диаллил-N,N'-диметиламмоний хлорида и диоксида серы различной молекулярной массы и додецилсульфата натрия. Комплексы охарактеризованы методами турбидиметрического титрования и лазерной дифракции/рассеяния света. Средний размер частиц полимер-коллоидных комплексов в зависимости от состава реакционной смеси и молекулярной массы полиэлектролита изменяются в интервале 150‒200 нм. Определены критические концентрации агрегации додецилсульфата натрия в присутствии сополимеров различной молекулярной массы. Показано, что молекулярная масса поликатиона оказывает значительное влияние на границы области появления фазы полимер-коллоидных комплексов и размер их частиц. Оценена способность частиц комплексов солюбилизировать молекулы плохо растворимых в воде веществ.

Методом лазерного рассеяния света исследовано образование дисперсий микрочастиц полиэлектролитных комплексов на основе поли-N,N-диаллил-N,N-диметиламмоний хлорида и карбоксилированного арабиногалактана, а также их комплексов с аминокислотами – гистидином, аргинином и лизином. Химическая модификация полиэлектролитов аминокислотами, вызывающая уменьшение содержания в макромолекулах ионогенных групп, приводит к увеличению размеров микрочастиц полиэлектролитных комплексов. Условия получения полиэлектролитных комплексных систем оптимизированы с точки зрения агрегативной устойчивости и размеров частиц. Установлено, что средний размер частиц полиэлектролитного комплекса линейно возрастает при увеличении мольного соотношения полианион : поликатион в комплексе. Показано, что выделенные из водных дисперсий осадки полиэлектролитных комплексов, хорошо сохраняются в виде сухих порошков, а при диспергировании в воде дают микрочастицы с размерами, сопоставимыми с размерами частиц исходных комплексов. Это открывает возможность решения проблемы длительного хранения физиологически активных микрочастиц.

Спектральными методами изучено взаимодействие в водных растворах йода с модифицированным фармакофорами (салициловой, 5 аминосалициловой, антраниловой кислотами) низкометоксилированным яблочным пектином (степень этерификации 10%). Определен состав, константы устойчивости йодсодержащих комплексов и рассчитаны стандартные термодинамические характеристики комплексообразования. Формирование молекулярных комплексов состава 1 : 1 для всех изученных систем контролируется энтальпийной составляющей (∆ Н ° < 0, ∆ S ° < 0). Обнаружено, что главными активными центрами, участвующими во взаимодействии с йодом, могут быть как гидроксильные, так и амино-группы модифицированной полисахаридной матрицы. Показано влияние степени метоксилирования полисахаридной матрицы и структуры модифицирующего полисахарид фармакофора на содержание йода, время высвобождения йода из образца, антимикробную активность.

Formation of dispersions of microparticles of polyelectrolyte complexes based on poly( N , N -diallyl- N , N -dimethylammonium chloride) and carboxylated arabinogalactan as well as their complexes with amino acids (histidine, arginine, and lysine) has been investigated by means of laser light scattering. Chemical modification of the polyelectrolytes with amino acids, inducing the decrease in the content of the ionic groups in the macromolecules, has led to the increase in the size of the polyelectrolyte complexes microparticles. The conditions for the polyelectrolyte complex systems preparation have been optimized in view of the aggregative stability and the particles size. It has been stated that mean size of the polyelectrolyte complex particles is increased linearly with the increase in the polyanion : polycation molar ratio in the complex. It has been shown that the sediments of the polyelectrolyte complexes isolated from the aqueous dispersions are stable in the form of dry particles and afford the microparticles with size comparable to this of the initial complexes upon dispersion in water. This feature opens the possibility to resolve the issue of prolonged storage of physiologically active microparticles.

The explosive eruption of the Hunga Tonga-Hunga Ha'apai volcano on January 15, 2022 triggered tsunami waves that were observed throughout the Pacific Ocean. In particular, the waves were recorded by several dozen deep-ocean DART stations located at source distances from hundreds to more than 10 thousand kilometers. Our study is aimed at analyzing tsunami waveforms recorded by DART stations in order to identify the formation mechanisms of this volcanogenic tsunami. Waveforms are processed using wavelet analysis. The arrival times of signals of different genesis are estimated making use robust physical assumptions, numerical modeling and satellite images. It has been found that in all records the tsunami signal is clearly observed long before the calculated moment of arrival of gravity surface waves caused by sources localized in the immediate vicinity of the volcano. On the records obtained by distant stations (~10000 km) dispersive gravity waves arrive with a delay of several hours after the signals following the passage of acoustic wave in the atmosphere. In addition to the analysis of waveforms, theoretical estimates of the amplitude of gravity waves in the ocean, caused by an acoustic wave in the atmosphere, will be presented. We also provide a theoretical estimate on how acoustic waves in the atmosphere manifest in pressure variations recorded by an ocean-bottom sensor. This study was funded by a grant of the Russian Science Foundation № 22-27-00415, https://rscf.ru/en/project/22-27-00415/.