High-molecular-weight samples of ladder polyphenylsilsesquioxane were synthesized by condensation of cistetraphenylcyclotetrasiloxanetetraol in ammonia. The samples were fractionated into 5 fractions each. Molar mass, hydrodynamic, and conformational properties of these fractions were determined in dilute benzene solutions using static and dynamic light scattering, chromatography, and viscometry. The molar masses of the fractions turned out to be very high, reaching 8000,000 g & sdot;mol-1. The exponents in the Mark-Kuhn-Houwink equations for intrinsic viscosity, radius of gyration and translational friction coefficient of macromolecules were found to be below 0.5, indicating the presence of branching in the prepared polysiloxane samples. It was shown that the number of branching centers is low and the linear chains between the branching points are very long, containing at least five Kuhn segments.

The structure and properties of sol-gel filled polyimide (PI) films were investigated as a protective coating for the low orbit devices. The organosoluble PI based on 4,4 '-(9-fluorenylidene)dianiline and 3,3 ',4,4 '-diphenyloxide tetracarboxylic acid and tris-(methyldiethoxysiloxy)aluminium (Al-siloxane) and tris-(methyldiethoxysiloxy)iron (Fe-siloxane) as precursors of nanoparticles were used. A comparative analysis of the curing of Al-siloxane and Fe-siloxane in pure state and in the polymer matrix was carried out by FTIR spectroscopy. The type of precursor metal atom has no significant influence on the thermal, mechanical, and dielectric properties of PI nanocomposites, however the filler and the type of precursor metal atom determine their resistance to atomic oxygen (AO). PI filled with nanoparticles based on Fe-siloxane (PI-[FeOSi]) exhibit a higher AO resistance than PI[AlOSi]. The SEM imaging showed that the protection mechanism of PIs with metallosiloxanes nanoparticles against the destructive AO effect is based on the formation of an external protective layer, morphology/continuity of which is determined by the nature of the metal atom. The protective layer on the PI-[FeOSi] surface is less susceptible to microcracking compared to the outer layer formed on the PI-[AlOSi] film.

Silica fillers have been a cornerstone in chemical technology due to their versatility, availability, and ease of integration into various formulations. Recent advancements, including chlorine-free synthesis of alkoxysilanes, have paved the way for alternative materials like polymethylsilsesquioxane (PMSSO). This study explores the structural evolution and properties of a hydrophobic PMSSO xerogel, synthesized through hydrolytic polycondensation of methyltriethoxysilane (MTEOS). PMSSO exhibits exceptional hydrophobicity, high specific surface area, and compatibility with polymer matrices, making it a promising filler for applications in rubber products, lubricants, and cosmetics. We developed a straightforward synthesis method for producing PMSSO xerogel that avoids toxic solvents and organochlorosilanes, ensuring safety and sustainability. The reaction conditions, particularly the amount of alkali and neutralization parameters, were found to significantly influence the properties of the final xerogels, such as specific surface area. Optimization of the synthesis parameters allow for obtaining PMSSO xerogels with a specific surface area about 600 m2/g. These findings underscore PMSSO’s potential as a versatile, eco-friendly alternative to conventional silica fillers, offering tailored properties for diverse industrial applications.

The kinetic regularities of the aminolysis of cyclocarbonates by alkoxysilanes bearing γ-aminopropyl substituents have been studied. New silyl-modified urethane oligomers were obtained that represent promising binding agents; their adhesive properties to various surfaces (glass, metal, wood) were studied. The cross-linked film materials based on them were obtained and their physical, mechanical, and thermal characteristics were studied.

Polysodiumoxy(methyl)siloxane is a highly functional polymer matrix that can be used for the preparation of both functional and non-functional polymers, including molecular brushes. To determine the molecular weight parameters of the matrix, as well as its chemical structure, it is necessary to develop an effective method of blocking functional (in our case, sodiumoxy) groups due to their high reactivity. At the same time, the blocking product should represent a complete non-functionalized replica of polysodiumoxy(methyl)siloxane. Since the obtained polysodiumoxy(methyl)siloxane can contain both sodium- and hydroxy groups in its composition, the presence of both types of functional groups should be considered in the blocking process. In this work, we investigated the blocking process of polysodiumoxy(methyl)siloxane and the influence of blocking conditions on the blocked product. We carried out several variants of blocking, which differed in the order and method of introduction of reagents, as well as in the temperature regime. The chemical structure and molecular weight characteristics of the obtained polymers were analyzed by 1H NMR spectroscopy and gel permeation chromatography (GPC), respectively. According to the blocking results, only in one case, complete non-functionalized replicas of polysodiumoxy(methyl)siloxane were obtained, which allows this technique to be used as a tool for the analysis of complex, highly functionalized organosilicon systems.

The synthesis of hybrid dendrimers composed of 1st, 2nd, and 3rd generation branched carbosilane macromolecules as the core, linked to a polyphenylene shell through a long hydrocarbon (C11) spacer, is described. This approach, employing a sequence of hydrosilylation and click reactions, starts with the preparation of 1-(11-azidoundecyl)-1,1,3,3-tetramethyldisiloxane followed by its reaction with allyl-functionalized carbosilane dendrimers, culminating in a CuAAC reaction with monoethynylhexaphenylbenzene. Structural analysis using SAXS and WAXS revealed the significant influence of the long alkyl spacers on crystal lattice formation, driven by the ordered motifs arising from the hexaphenylbenzene terminal units.

In this work, we propose an approach for obtaining polydimethylsiloxanes of various structures, both linear and branched, by a ring-opening polymerization (ROP) of hexamethylcyclotrisiloxane initiated by silanols in liquid ammonia. In this case, ammonia acts both as a solvent and as a catalyst. Such hydroxy-containing compounds as Ph3SiOH, Ph2Si(OH)2, PhSi(OH)3 and cis-[PhSi(O)OH]4 are used as initiators.

Poly(siloxane-urethane)s are an unique class of organosilicon copolymers that combine valuable properties of both silicones and polyurethanes. In this study a series of polymer films based on poly(siloxane-urethane) was prepared and fully characterized. A modern synthetic route developed by our group earlier based on utilization of organoeuropiumsiloxanes as luminescent agents for the preparation of luminescent polymers was used. The effect of the nature of phenyleuropiumsiloxanes of different structures on mechanical, thermal as well as optical properties of composites was studied. It was shown that oligomeric phenyleuropiumsiloxane in combination with β-diketone ligand provides the most prospect composite materials with intense luminescence.

In the original international version of the article, the second author’s name was specified incorrectly.

Silicones are one of the most important materials, without which it is difficult to imagine human life in the 21st century. Hydrosilylation is widely used to obtain functional silanes and siloxanes. This review summarizes the available data on the kinetics of the interaction of silyl hydrides in the composition of different molecules with various alkenyl substrates under the hydrosilylation reaction conditions.

In this study, we report the synthesis and characterization of aminated poly(methyl silsesquioxane)-based hydrogels ((AP/MS)SO-hydrogels) as potential enzyme-sensitive vehicles for antianemic drugs. The hydrogels were synthesized via sol–gel polymerization and functionalized with amine groups. Characterization techniques included Congo red assay, Brunauer–Emmett–Teller (BET) surface area analysis, scanning electron microscopy, elemental analysis, 13C NMR, 29Si NMR, and ATR-FTIR spectroscopy and microscopy of hydrogels. The sorption of ferric chloride and ferrous D-gluconate, as well as complexes of ferrous D-gluconate with HPCD, was evaluated. Crosslinking of the gel with bifunctional agents was performed to create a new amide enzyme-sensitive bond, followed by infrared characterization of the crosslinked product. Trypsin-mediated degradation studies demonstrated the sensitivity of the hydrogel to enzymatic cleavage under model conditions. Iron release experiments in gastric and intestine-simulating media confirmed prolonged release. Overall, our findings suggest that aminated PMSSO-hydrogels hold promise as versatile and biocompatible carriers for targeted delivery of antianemic agents, warranting further exploration in preclinical and clinical applications.

This work presents a new approach to recycling silicone waste: depolymerization in ammonia. The optimal depolymerization conditions (150 degrees C, 0.25 mL H2O, 24 h) to achieve complete polymer conversion were developed using a model siloxane fluid PMS-200. The method performance was demonstrated on model unfilled silicone rubbers obtained by classical methods of curing silicone elastomers such as hydrosilylation, condensation of functional groups and radical polymerization in the presence of benzoyl peroxide. The versatility of this approach for recycling both linear silicones (fluids and gums) and filled rubbers (fillers of different nature) was demonstrated. The completeness of the depolymerization and the analysis of the low molecular weight products were tested by SEC, GC and 29Si NMR spectroscopy. The scalability of the process has been demonstrated.

This work presents the results of a study on the CuCl-catalyzed reaction of silicon with dimethyl carbonate (DMC) in a high-pressure mechanochemical reactor (HPMR) at 250 degrees C. The reaction was carried out in the presence of both single promoters (Al, Zn, Sn) and their various combinations. The best selectivity toward dimethyldimethoxysilane was obtained using Sn (70%) at a silicon conversion of 30%. The best performance for silicon conversion (73%) was achieved with the combined use of Zn and Sn. The selectivity toward dimethyldimethoxysilane in this case was 38%. The influence of the type and number of promoters, as well as the material of the grinding bodies (GBs) on the selectivity and conversion of silicon in its reaction with DMC were investigated. The liquid reaction products were characterized by GC, GC-MS, 1H, 13C, 29Si NMR spectroscopy. Spent contact masses after syntheses were investigated by PXRD, SEM-EDX and XPS.

The present review is devoted to the search for the possible methods to synthesize siloxane molecular brushes (MBs). Wide diversity of chemical nature and architectures offered by MBs become possible due to the development of state-of-the-art synthetic methods. The review provided a detailed analysis of the possible synthetic approaches to MBs, their advantages and drawbacks. The possible applications of MBs are also discussed. The facts that siloxane MBs can demonstrate unique properties, can be of interest for practical applications, and the suggested synthetic approaches have prospects for further development were underlined.

The synthesis of mixed polyorganosiloxanes is nowadays of paramount industrial importance for obtaining new copolymers by the simple ring-opening polymerization. In this work, the synthesis and characterization of a new mixed cycle with one methylbenzyl moiety are presented.

A series of poly[dimethyl(methylbenzyl)siloxanes] with different content of the methylbenzylsiloxane fragments have been synthesized. Structure of the polymers has been confirmed by means of 1Н and 29Si NMR spectroscopy. Thermal properties of the polymers have been investigated by means of differential scanning calorimetry and thermogravimetric analysis. It has been found that the copolymer crystallization is suppressed at the content of the methylbenzylsiloxane fragments on the copolymer of 3 mol

The rheological and rheokinetic properties of the compositions based on low-molecular rubber polyisoprene and MQ copolymer particles with decyl terminal groups were studied. The effect of the ratio of M and Q units in the copolymer on the rheological and mechanical properties of the compositions was analyzed. An increase in the length of a hydrocarbon substituent in M units was shown to lead to an increase in the affinity of the copolymer to the carbon-chain polymer matrix. An increase in the content of Q units facilitates the growth of the elastic modulus of the cured composites.

The temperature dependences of the heat capacities of carbosilane dendrimers of the third and sixth generations with ethyleneoxide terminal groups are examined for the first time by means of precision adiabatic vacuum calorimetry at temperatures between 6.5 and 350 K. In this temperature range, physical transformations are observed and their standard thermodynamic characteristics are determined and discussed. The standard thermodynamic functions are calculated per nominal mole of a chosen unit using the obtained experimental data: C° p (T), H°(T) - H°(0), S°(T) - S°(0), and G°(T) - H°(0) in the interval T → 0 to 350 K, and the standard entropies of formation at T = 298.15 K. The low-temperature (T ≤ 50 K) heat capacity is analyzed using the Debye theory of specific heat and a multifractal model. The values of fractal dimension D are also determined, and conclusions on the investigated structures’ topology are drawn. The corresponding thermodynamic properties of the studied dendrimers are compared as well.

The copolymers containing alternating siloxane and urethane units in the chain as well as ester moieties were synthesized by the azide–alkyne cycloaddition without application of a solvent and copper salts as catalysts. The resulting copolymers were analyzed by NMR spectroscopy and gel permeation chromatography.

The synthesis of allyl-containing PDMS telechelics from octamethylcyclotetrasiloxane and 1,3-diallyl-1,1,3,3-tetramethyldisiloxane as a stopper by the anionic ring-opening of a siloxane ring is presented. A series of the polymers with the molecular weights from 1000 to 12000 were obtained and characterized by gel permeation chromatography and 1H NMR spectroscopy. The molecular weights of the resulting polymers correspond to the given ones.