Published data on methods for the preparation of liquid crystalline phenyl benzoate derivatives were summarized. The results of studies on the mesomorphic properties of phenyl benzoates were analyzed. The available literature and authors' research data on the application of mesogenic phenyl benzoate derivatives in medicine and in the chemistry of macroheterocyclic compounds, as well as in polymer chemistry and technology were presented.

In this paper, we investigated two types of silicas obtained by the sol-gel synthesis (silica 1) and solgel synthesis of endotemplates (fructose) (silica 2). In the first phase of work, the surface characteristics of the synthesized silicas were evaluated. Area measurement and pore volume of silica samples showed that the surface of silica 2 had a narrow slitlike pores, and the pore size was 3.15–3.17 nm. Thermochemical studies of silica showed that the content of hydroxyl groups per 1 g of silica was greater in the case of silica synthesized by endotemplate technology. The obtained data on the texture parameters and chemical activity of the surface were used in the study of systems containing surfactant and silica in aqueous media. Common for particles of synthesized silica is that the form of particles in the solutions remains spherical and the zeta potential decreases. Moreover, the neutralization of the surface charge of silica 2 takes place to a greater extent than the neutralization of the charge on the surface of particles of silica 1. The greatest practical interest may be the pre-foaming solution with the addition of silica 2, because the maximum lifetime was recorded in this solution.

Синтезированы шесть потенциально мезогенных каламитных трициклических соединений, которые в качестве одного из терминальных заместителей содержат (S)-2-метил-1-бутилокси-хиральный фрагмент. Строение полученных веществ установлено методами элементного анализа, спектроскопии ЯМР Н и С, масс-спектрометрии. Методом DFT B3LYP оптимизированы структуры соединений, рассчитаны дипольные моменты и поляризуемость. Методом дифференциально-сканирующей калориметрии определены температуры и энтальпии фазовых переходов. Обсуждается влияние строения соединений на их мезоморфные свойства. Ключевые слова: синтез, спектроскопия, хиральный терминальный заместитель, квантовохимические расчеты, мезофаза, хиральная нематика.

Differential thermogravimetric analysis was used to study the thermal oxidative degradation of peat samples from different districts of the Ivanovo Region. The study was performed in nonisothermic conditions. It was found that the thermal oxidative processes involve a few steps. Kinetic characteristics [activation energy (E a), preexponential factor (ln A), and reaction order (n)] were estimated for each step. It was found that the limiting stage of the entire process is a chemical reaction. The resulting data can be used to develop prognostic models for peatbog combustion.

Приведены результаты использования комплексной методики анализа поведения цементных составов, содержащих силикатные добавки, в условиях высокотемпературного нагрева. В ходе эксперимента расширены условия испытаний, принятые в стандартных методиках по оценке высокотемпературных воздействий на цементные составы. К общепринятым методикам добавлены исследования термохимических свойств на уровне структурообразования исследуемых образцов. Проведена корреляция результатов, полученных разными методами. Показано, что при динамичном высокотемпературном нагреве цементного камня происходит его разложение на различные химические составляющие, формируется структура композиционных вяжущих в процессе гидратации, а также улучшается ряд теплофизических свойств цементных составов, содержащих силикатные добавки.

The melt flow indexes of polyethylene modified with industrial and liquid-crystalline additives were determined. The wetting angles of polyethylene films by water and glycerine were measured, and their tribological characteristics were assessed. The effect of the modifier on the properties of low-density polyethylene is discussed.

The first five organic compounds of the azo- and azoxybenzene classes have been tested as light and heat stabilisers of polyvinyl chloride. Their high effectiveness by comparison with industrial antioxidant has been demonstrated.

This paper presents a study of the capability to modify cement by mechanical activation of sodium silicate water solution. Admixtures or blends of binding agents were employed for modifying concrete properties. The liquid glass is applied to protect from chemically or physically unfavorable environmental impacts, such as acidic medium and high temperature. The sodium silicate is a high-capacity setting accelerator. The increasing of the liquid glass proportion in the mix leads to the degradation of the cement paste plasticity and for this reason it is necessary to reduce the amount of liquid glass in the cement paste. The activation of dilute water solution of sodium silicate into rotary pulsating apparatus directly before tempering of the cement paste is an effective way to decrease mass fraction of liquid glass in the cement paste. The results of the combined influence of liquid glass and mechanical activation on physicochemical processes taking place in cement stone are represented in this research. Thermogravimetric analysis was used in order to study cement blends. Thermogravimetric analysis of modified cement stone assays was performed by thermo analyzer SETARAM TGA 92-24. The results of the analysis of phase transition taking place under high-temperature heating of cement stone modified by the mechanical activation of the water solution of the sodium silicate were introduced. Thermograms of cement stone assays were obtained at different hardening age. The comparison of these thermograms allows us to come to a conclusion on the formation and the retention during long time of a more dense structure of the composite matrix mixed by the mechanical activation of sodium silicate water solution. The relation between the concrete composition and its strength properties was stated. Perhaps, the capability of modified concrete to keep calcium ions in sparingly soluble hydrosilicates leads to the increase in its durability and corrosion resistance.

For the first time, two organic compounds of the cyanobiphenyl class were tested as light and heat stabilisers of polyvinyl chloride. Their universality and high effectiveness by comparison with an industrial stabiliser were demonstrated.

Modification of the liquid crystal composite material LC-654 by small additions of polar pnitroaniline was carried out. Temperatures of the nematic - isotropic liquid phase transition of mixtures with various content of non-mesogen were determined. Temperature dependences of dielectric constant, refractive index, dielectric and optical anisotropy of the studied samples were obtained. The influence of p-nitroaniline on physical properties of LCD-654 is discussed.

In given study the plasticized PVC film samples containing anisotropic azo - azoxybenzenes with therminal substituents were obtained. The plasticized PVC film samples modified mesogens were established to possess the thermal stability higher the same parameters for PVC film samples containing industrial stabilizer as well as good physical and mechanical properties.

The plasticized polyvinylchloride films containing anisotropic azobenzenes and phenylbenzoates with terminal substituents, one of which was the 2,2-dicyanoethenyl fragment were obtained. It was found that the plasticized polyvinylchloride films modified by mesogens have better physicalmechanical characteristics than the films containing commercial stabilizer.

Thermal analysis of seven mesogenic phenylbenzoates, azo- and azoxybenzenes with polar terminal substituents (-OH, -CHO, -CN, etc.) was carried out. It was found that the phase transition temperatures, determined by DTA method, are in satisfactory agreement with the thermo-microscopic data. Thermal stability of the studied substances was estimated.

Mesomorphic properties of synthesized azobenzenes containing 2,2-dicyanoethenyl fragment were studied by polarization thermomicroscopy and differential scanning calorimetry methods. The type of mesomorphism, temperatures of phase transitions and temperature intervals of mesophase existence were determined. The phase diagram of a binary mixture of 4-(6-hydroxyhexyloxy)-4'-(2,2dicyanoethenyl) azobenzene - 4-heptyloxy-4'-cyanobiphenyl was drawn. Dipole moments for three synthesized substances were determined. Thermal analysis of two homologues was made and onset temperatures of decomposition were determined. The influence of 2,2-dicyanoethenyl substituent on properties of azobenzenes is discussed.

Optimum conditions for the synthesis of compounds of two homologous series: 4-alkoxy-(C-,(6) C-7, C-8, C-9) and 4-(n-hydroxyalkoxy)-4'-(2,2-dicyanoethenyl) azobenzene (C-6, C-8, C-9, C-10) were worked out. Structural characterization of the compounds was carried out by the methods of elemental analysis, IR-, H-1 and C-13 nuclear magnetic resonance spectroscopy. UV-spectra of the synthesized compounds were obtained. Melting points and molar extinction coefficients were determined.

Procedures were developed which made it possible to synthesize in good yields homologs of 4-acryloyloxyphenyl 4-alkoxybenzoates (C3, C5, C7, C8) and of 4-(2,3-epoxypropoxy)phenyl 4-alkoxybenzoates (C5, C7). The substituted phenylbenzoates obtained exhibit the enantiotropic nematic mesomorphism in a sufficiently wide temperature range. The studied compounds have absorption maxima in the near UV region and a high temperature of decomposition beginning.