The methodics of characterization of 2D-nanofiller tactoids structure in polymer matrix of nanocomposite was proposed, which shown that the indicated tactoids are fractal objects with dimension of 1.75-2.16. This variation of tactoids structural state is due to interfacial interactions. It has been shown within the framework of reinforcement percolation theory, that structure of tactoids is single factor, defining reinforcement efficiency is characterized by its ability to create interfacial regions.

Possible prospects of application of porous polymer matrices with closed pores as selective protonconducting membranes are discussed. Such systems are well known; however, their application to mass transfer is traditionally underestimated. Nevertheless, precisely such structures are attractive as membranes of redox flow batteries. In the present paper, possible approaches to obtaining such systems (including polystyrene-based) using supercritical carbon dioxide are shown.

The process of open-porous structure development in high density polyethylene (HDPE) films during uniaxial deformation in supercritical carbon dioxide (SC-CO2) fluid at 35 degrees C and 10 MPa has been studied and visualized by means of atomic force microscopy. We suggest that the supercritical fluid act as adsorption-active medium, and the porous structure is developed via the crazing mechanism due to the increasing the distance between of lamellae and the formation of oriented separate fibrils in the intercrystallite space. Effective bulk porosity of the films has been up to 40%. Small-angle X-ray scattering studies and ethanol permeability measurements have revealed that the pores and fibrils are about 10 nm in diameter. The prepared nanoporous materials exhibit good vapor permeability. Structural and mechanical behavior of the prepared porous films has been investigated. Large reversible deformation (up to 80%) of HDPE in the SC-CO2 has been observed. Repeated drawing of the shrunk films in air under ambient conditions has led to the open-porous structure recovery.

Рассмотрены возможные перспективы использования пористых полимерных матриц с закрытыми порами в качестве селективных протонпроводящих мембран. Такие системы хорошо известны, однако их применение для приложений, связанных с массопереносом, традиционно недооценено. Тем не менее, именно подобные структуры привлекательны в качестве мембран окислительно-восстановительных проточных батарей. В работе показаны возможные подходы к получению таких систем с помощью сверхкритического диоксида углерода, в том числе на основе полистирола.

A new synthetic route was developed to three-module type potential hydrophobic agents, with the molecule consisting of an N-[3-(triethoxysilyl)propyl]amide anchor part (I), a connecting unit formed upon 1,3-propansultone ring cleavage (II), and a polyfluoroheptyloxy functional hydrophobic spacer (III). Proceeding from commercially available polyfluorinated heptanols 1a and 1b and 1,3-propanesultone 3, potassium sulfonates 4a and 4b were prepared. The reaction of 4a and 4b with phosphorus oxychloride resulted in the first synthesis of fluorine-containing sulfonyl chlorides 5a and 5b, which were reacted with 3-aminopropyltriethoxysilane 6 to give the target N-[3-(triethoxysilyl)propyl]-3-(polyfluoroheptyloxy)propane-1-sulfonamides 7a and 7b. The structures of the compounds were proved by NMR spectroscopy, mass spectrometry, and elemental analysis. The studies of their hydrophobizing properties are in progress.

For the first time the influence of pressure of chitosan solutions in carbonic acid on the adsorption of chitosan onto a collagen tissue of biological heart-valve prostheses and on the structure of the resulting biocomposite was studied. It turned out that the dependence of an amount of the chitosan adsorbed onto the collagen tissue has bell-shaped form reaching a maximum adsorption of about 0.8 weight. % at 30-40 MPa and then falling to 0.3 wt. % with further pressure increase up to 50 MPa. It was found that this treatment leads to a significant change of the morphology of the tissue surface which depends on the pressure in the system. It was also revealed that under pressure growth collagen fibrils are compacted in the tissue bulk which leads to the extrusion of the polymer embedded in the collagen matrix.

A protonation of ethynylferrocene by nafion in sc-CO2 in the presence of triphenylphosphine (PPh3) or 1,2-bis (diphenylphosphino)ethane (DPPE) leads to a formation of novel (1-ferrocenylvinyl)phosphonium or ferrocenyl substituted bisphosphonium salt isolated as tetrafluoroborates 3 and 4, respectively. Ferrocenyl substituted bisphosphonium tetrafluoroborate 4 undergoes the hydrolytic cleavage of the P+-C(Fc) bond in the presence of Al2O3 at 25 degrees C to form ferrocenyl substituted phosphinyl phosphonium tetrafluoroborate 5. Complexes 3-5 were completely characterized by NMR spectra and their molecular structures elucidated by X-ray studies.

A mixture of water/carbon dioxide is a "green" perspective solvent from the viewpoint of biomedical applications. Clathrate hydrates are formed this solvent under certain conditions and a very interesting question is the impact of clathrates hydrates on the structure and properties of bovine pericardium, which is used in biomedicine, in particular as a main part of biological heart valve prostheses. The aim of the present work is to investigate the influence of clathrates on the structure and mechanical properties of the collagen tissue treated with chitosan in H2O/CO2 mixtures under pressure 3.0-3.5MPa and temperatures 2-4°C. It was first found that the clathrate hydrates in this media due to the strong fluctuations "bomb" collagen tissue of bovine pericardium, which is manifested in the appearance of numerous small gaps (pores) with mean size of 225±25nm and large pores with size of 1-3μ on the surface and within collagen matrices. High porosity leads to averaging characteristics of the organization structure in tissues with different orientation of the collagen fibers. As a result, the mechanical properties of the collagen tissue with a different orientation of the collagen fibrils become similar, which is quite different from their original properties. The structural changes caused by the influence of the environment clathrate hydrates led to a significant decrease of the tensile strength (30-47% in total, p<0.05) and initial elastic moduli (74-83%, p<0.05). However, the final elastic moduli and the maximum tensile virtually unchanged compared to the control. Nevertheless, it was found that the direct deposition of chitosan from the H2O/CO2 mixtures with clathrate improve the mechanical-strength properties of the porous matrices. We believe that these improved mechanical properties are achieved due to particularly deep and uniform impregnation of the collagen matrix with chitosan from its pressurized solutions in H2O/CO2 mixtures.

The effect of pressure in solutions of chitosan in carbonic acid with the AgNO3 precursor on the structure of cast nanocomposite films with silver nanoparticles has been studied for the first time. The size of silver nanoparticles can be controlled by varying pressure in carbonic acid.

Cation CpFeC5H4–C+=CH2 was obtained by protonation of FcCCH with Nafion superacid in DMF or scCO2 and characterized by NMR spectroscopy. The protonation in the presence of SMe2 or PPh3 affords new onium derivatives, which were isolated as the tetrafluoroborate salts.

A method of synthesis of new fluorine-containing tetraamine, 2,2-bis[4-(3,4-diaminophenoxy) phenyl]hexafluoropropane, has been developed; the tetraamine has been used as the initial compound for preparing poly(phenylquinoxaline)s in both supercritical carbon dioxide and solution. Thermal characteristics of fluorine-containing poly(phenylquinoxaline)s have been studied. There is a bimodal particle size distribution at the used polymer concentration (C pol = 0.1 wt %) according to dynamic laser light scattering data.

A study of the formation of poly(phenylquinoxaline)s in supercritical carbon dioxide was performed. It was found that the reaction conditions of cyclopolycondensation had a significant impact on the formation of polymers. When using certain catalysts, soluble polymers were obtained which were cast into thin films and some of their properties were then studied. (C) 2016 Elsevier B.V. All rights reserved,

A magnetic pyrocarbon composite containing nanoparticles with an overwhelming predominance of zerovalent iron has been synthesized. The nanocomposite has a core–shell–matrix structure in which Fe0 nanoparticles with an average size of 50 nm are located in the pyrocarbon matrix and coated with a ferrite shell preventing their aggregation and oxidation. The composite is distinguished for its high thermal stability, magnetic properties 59 G cm3/g, and electrical conductivity as high as that of graphite.

The effect of the clathrate hydrate environment in the water/carbon dioxide system on the structure of the chitosan-coated collagen xenograft tissue was demonstrated. The collagen xenograft tissue treated in this environment is a porous material with a pore size of 50–500 nm having also micrometer size (1–3 μm) pores. The high porosity results in averaging of the structural organization features in xenograft tissues with different orientation of collagen fibrils. Treatment of xenograft tissues in the H 2 O/CO 2 environment in the presence of clathrate hydrates allows the manufacture of a nanoporous biodegradable material suitable for biomedical applications.

A process has been proposed for hydrophobizing an inorganic porous material consisting of silica fibers using fluoroalkane dissolution in supercritical carbon dioxide. The process allows one to produce thin, homogeneous polymer coatings both on the surface and in the bulk of the material, ensuring that the material has excellent hydrophobic properties, which significantly improves its performance parameters and extends its potential application field.