An atomic force microscopy study of hybrid polymeric membranes: Surface topographical analysis and estimation of pore size distribution

© 2016, Pleiades Publishing, Ltd.The surface morphology of polymeric membranes as organic–inorganic block copolymers has been studied by atomic force microscopy (AFM). These hybrid block copolymers have been obtained by the polyaddition of toluene 2,4-diisocyanate to macroinitiators and the addition of oligomeric polyhedral оctaglycidyl silsesquioxane (Gl-POSS) as a bulky branching agent in a concentration range of 0.1–15 wt %. The AFM study of the morphology made it possible to determine the main roughness parameters and to perform topographical analysis of the surface of the polymers. The pore size distribution was evaluated by histogrammic approximation with the use of the Gauss distribution. The hypothesis of the normalcy of distribution of the experimental sample of pore diameters was confirmed by a combined criterion and Pearson’s chi-square goodness-of-fit test. The effect of the Gl-POSS concentration on the surface morphology and the microstructure of the organic–inorganic polymeric membranes was found to be nonmonotonic over the test concentration range

Effects of temperature and concentration factors on the conformational state and reactivity of potassium poly(oxyethylene glycolate)

With the use of pulsed magnetic-field gradient NMR, self-diffusion coefficients of potassium poly(oxyethylene glycolate) macromolecules and solvent molecules (acetone) and the variation in the dimensions of supramolecular structures of potassium poly(oxyethylene glycolate) with temperature and its concentration in acetone are measured. It is discovered that the temperature dependences of change in the rate constants of reactions that proceed during the interaction of potassium poly(oxyethylene glycolate) with 2,4-toluylene diisocyanate do not fit Arrhenius coordinates. © 2010 Pleiades Publishing, Ltd

Mössbauer study of structurally ordered iron coordination compounds and polyurethanes crosslinked by them

The structure of a metal-complex system based on ferric chloride and monoethanolamine and the products of interaction of this system with ε-caprolactam and a urethane prepolymer was studied by Mössbauer spectroscopy. It was found that iron ions in the coordination compounds of interest are linked with one another in a chain structure via chloride bridges. The columnar structure of metal complexes, the presence of magnetic ordering in these complexes below 70 K, and the feasibility of formation of metal complexes ordered in the same manner in a flexible-chain polymer matrix containing electron-donating groups were revealed. © Pleiades Publishing, Inc., 2006

Framed aromatic polyurethanes based on an anionic macroinitiator, 4,4'-diphenylmethane diisocyanate, and 4,4'-dihydroxy-2,2-diphenylpropane: Synthesis and characterization

© 2017, Pleiades Publishing, Ltd. Polyurethanes composed of aromatic components are synthesized using the catalytic effect of potassium alcoholates on the reaction of urethane formation occurring with participation of 4,4'-dihydroxy-2,2-diphenylpropane, 4,4'-diphenylmethane diisocyanate, and polyisocyanate, which is a mixture of 4,4'-diphenylmethane diisocyanate and its branched derivatives. In the case of 4,4'-diphenylmethane diisocyanate, segmented polyurethanes with the predetermined length of the rigid block are formed, while the use of polyisocyanate gives rise to framed aromatic polyurethanes. The use of macroinitiators as carriers of potassium alcoholate groups does not cause microphase separation of flexible and rigid segments

Immobilization of organic reagents on optically transparent mesoporous polymers and its analytical use

© 2015 Pleiades Publishing, Ltd. Sorption of organic reagents Arsenazo III and 1-(2-pyridylazo)-2-naphthol onto optically transparent mesoporous polymers prepared from macroinitiators and toluene 2,4-diisocyanate was studied. The possibility of preconcentration of organic reagents and their complexation with Cu(II) and Ca(II) ions in the polymer pore voids was demonstrated. Experiments on spectrophotometric analysis using the polymeric support showed that the lower limit of determination was 20 μg mL-1 for Ca(II) and 2 μg mL-1 for Cu(II)

Принципы бариатрической хирургии (обзор литературы)

Surgical treatment of obesity and associated diseases, like any other field of practical medicine, is based on certain laws and conditions. All the principles of bariatric surgery were formulated in the process of accumulating a positive and negative experience of using various surgical interventions. The article presents an historical perspective on the evolution of views on the fundamental principles of the operative treatment of obesity and associated diseases.Хирургическое лечение ожирения и ассоциированных с ним заболеваний, как и любая другая область практиче­ской медицины, основывается на определенных законах и условиях. Все принципы бариатрической хирургии были сформулированы в процессе накопления положительно и отрицательного опыта применения различных по меха­низмам действия оперативных вмешательств. В статье с исторических позиций представлена эволюция взглядов на основополагающие принципы оперативного лечения ожирения и ассоциированных с ним заболеваний

Investigation of supramolecular organization of polyetherisocyanatesiloxanes

The characteristics of the supramolecular organization of polyetherisocyanatesiloxanes are inferred from measurements of the temperature dependence of the dielectric loss tangent. It is shown that the mutual influence of macromolecular components on the formation of interpenetrating polymer network depends on the prescription and temperature conditions of synthesis. © 2011 Pleiades Publishing, Ltd

Synthesis and properties of novel polyurethanes based on amino ethers of boric acid for gas separation membranes

© The Royal Society of Chemistry. Herein we present the structural and mechanical properties of polyurethanes synthesized from amino ethers of boric acid for gas separation. The polymers were characterized by light scattering methods, conductivity measurements, thermal gravimetric analysis, Fourier transform infrared spectroscopy, and atomic force microscopy. Additionally, the permeability of ammonia and carbon dioxide, as well as the selectivity for their diffusion and resultant impurity are presented. The results illustrate the steric hindrance, resulting in a branched architecture borate formation, leads to intermolecular complexation which may assist the polymer in ammonia diffusion selectivity

The effect of microporous polymeric support modification on surface and gas transport properties of supported ionic liquid membranes

© 2015 by the authors; licensee MDPI, Basel, Switzerland. Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested for He, N2, NH3, H2S, and CO2 gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF6] and [emim][Tf2N]. The modification of SILMs by nanosize silica particles leads to an increase of NH3 separation relatively to CO2 or H2S

Оценка риска осложнений в бариатрической хирургии

Introduction. Surgical treatment of obese patients includes a high risk of complications.Material and methods. The article presents the analysis of the informativeness and reliability of OS-MRS, E. Livingston, P. Turner scores in predicting postoperative complications in patients with overweight and metabolic disorders.Results. According to the study, the OS-MRS score was the most reliable.Введение. Хирургическое лечение пациентов с ожирением несет высокий риск осложнений.Материал и методы. Представлен анализ информативности и достоверности шкал OS-MRS, E. Livingston, P. Turner в прогнозировании послеоперационных осложнений у пациентов с избыточной массой тела и метаболическими нарушениями.Результаты. По данным проведенного исследования, шкала OS-MRS является наиболее достоверной