Sol-Gel Preparation of Ceramic Coatings for Electrical, Laser, Space Engineering and Power

The brief review, based on long-term experience of authors on preparation of temperature-resistant electric insulating and optical light-reflecting ceramic coatings on metal surface is offered. The main components of TEOS-, H₃PO₄- and alkali silicates-derived sols and suspensions for deposition of ceramic coatings are listed. Some features of preparation of the coatings from the sols containing fillers are analysed. Two approaches to improve bending and electrical strength of flexible insulation are developed. The techniques of synthesis of modified fillers for preparing gas-proof and anticorrosive coatings are offered. The wide functional possibility and extensive list of application areas of the coatings and some materials prepared from sols with fillers, including on far prospect are given.     

Biopolymer composites based on modified lignin and nanocellulose

New composite lignocellulose materials were prepared using modified lignin and nanocellulose. The materials were studied by elemental and thermal gravimetric analysis, and their tensile tests were performed. The results obtained show that addition of nanocellulose to modified lignin makes possible its use as filler in paper production.     

Association of Chitosan in Aqueous-Alcohol Solutions

The association of chitosan in aqueous-alcohol solutions is studied via probe fluorescence spectroscopy and dynamic light scattering. It is shown that, if a certain critical concentration is reached, the associates of macromolecules 12–38 nm in size are formed in chitosan solutions. The addition of 5–60 vol % ethanol to the solvent leads to reduction in the critical association concentration. The tendency of chitosan macromolecules toward association is the most pronounced at 34 vol % alcohol.     

Composition and structure of platinum-containing thin composite films prepared from silica sols

Chemical processes that can occur during aging of sols based on water–alcohol solutions of tetraethoxysilane (TEOS) and hexachloroplatinic acid and during formation of films from these sols are analyzed by the results of visible and UV spectroscopy and X-ray powder diffraction. The sizes and compositions of the platinum particles that are formed in xerogels and in thin films on the nanometer and submicron levels are estimated based on X-ray crystallography, energy dispersive spectral analysis, high-resolution scanning and transmission electron microscopy, and grazing incidence small-angle X-ray scattering studies.     

Synthesis of new [2]rotaxane including a macrocyclic receptor and a photochromic unit

The novel photochromic [2]rotaxane based on chromene molecule introduced into a crown-containing macrocyclic receptor was synthesized. The photochemical properties of rotaxane could be modified by the complexation of the crown ether moiety.     

Photosynthesis of oxygen in the forest ecosystem and its albedo as major factors of prevention of current civilization from the oxygen and freshwater disaster

The interrelation between the resource-forming and environment-forming functions of the phytosphere, on the one hand, and their consumption by the current civilization, on the other hand, is considered. It was shown that the world technogenic consumption of oxygen in excess of its influx to the atmosphere is 10¹⁰ t per annum, the globe average vegetation cover has gradually passed from forest to steppe, and the critical movement from steppe to desert is going now. The ecological-economic harmonization of the consumption of the environment-and resource-forming functions of the forest is needed.     

Maximum acceptable deviations from additivity in the photometric analysis of two-component mixtures by Firordt’s method

Photometric analysis of mixtures by Firordt’s method yields relative errors that do not exceed the specified limits only if the deviations from additivity at the analytical wavelengths do not exceed (in their numerical value) their own critical values (δA _crit). These deviations depend on the ratio of component concentrations. By virtue of the analytical geometry technique, we derived equations for the evaluation of δA _crit. These equations allow one to predict the possibility of the precise determination of two components in a mixture under investigation at one and the same set of wavelengths. The developed algorithm was verified on 40 model mixtures of organic compounds.     

Development of a convenient synthetic route to aminochromenes via Buchwald C-N coupling

A convenient new synthetic route to p-aminophenylaminobenzo- and naphthopyrans was developed via palladium-catalyzed C-N coupling. It was demonstrated that novel targeted aminoderivatives reveal photochromic properties. The structure of intermediate p-nitrophenylaminochromenes was confirmed by X-ray crystallographic analysis.