thermal analysis

The present paper discusses the development of new, environmentally friendly composite materials with advantageous properties. These composites are based on plant raw material - pine sawdust and trimethoxysilylated polystyrene (TMSPSt). The binder for the composites was obtained by our research group and used in conjunction with different degrees of silylation (15-35%), in the presence of various organic and inorganic additives, fire retardants, and antioxidants. It simultaneously acts as a reinforcing agent.

The bentonite from the Ilnytsky deposit was modified by sorbtion of chitosan on the surface of its particles in an aqueous suspension. It was found that there is an optimal concentration of chitosan (at a constant bentonite content in the suspension) that maximizes the sorption rate of chitosan macromolecules, which leads to improved flocculation and sedimentation of the suspension. Additionally, it was demonstrated that the chitosan sorption on suspension particles significantly increases with increasing pH from 3 to 9.5.

The influence of dispersion on the structural and sorption properties of the Transcarpathian clinoptilolite of the Sokyrnytske deposit was investigated by the method of complex thermal analysis. For a sample with a grain size of 0.14 mm, the effect of heat treatment on the ability to sorb water vapor was investigated. Thermal activation of clinoptilolite was carried out at temperatures of 200°C, 300°C, 400°C.The sorption capacity of natural and thermally activated clinoptilolite samples with relative to water vapor was investigated by thermal analysis.

Описано спосіб розрахунку теплофізичних характеристик композитних матеріалів зі складною внутрішньою структурою на основі дискретної моделі, що будується за методом теплоелектричних аналогій.

This paper consider the method of calculation the thermophysical characteristics of composite materials with complex internal structure based on the discrete model that is constructed by the method of thermal-electric analogies.

The filtration method of gradual dehydration of Iron(II) sulfate heptahydrate hase been proposed. Based on the generalization of experimental data of hydrodynamics, the calculated dependence Euзовн=155∙Reзовн-0,55∙Hdч  was obtained, which makes it possible to determine theoreticallypressure losses in the stationary layer of FeSO4·7H2O.According to the results of complex thermal analysis, the regularities of the gradual dehydration process of FeSO4·7H2O have been established in different temperature intervals.

This work reveals a method of complex thermal and chemical activation of natural clinoptilolite from Sokyrnytsky deposit. The chemical activation of a mineral was carried out by HCl solutions treatment at various ratios of liquid-to-solid phases. With the use of thermal and infrared (IR) spectroscopic analyses, the adsorption property of a natural and activated clinoptilolite has been examined for water vapor. The ability of complexly activated clinoptilolite to adsorb direct dyes from their aqua solutions has been investigated.

Biogenic surfactants (rhamnolipid biocomplex, dirhamnolipid and exopolysaccharide) and polyhydroxyalkanoate biopolymer which are the new biosynthesis products of Pseudomonas sp. PS-17 strain have been obtained. The thermal transformation of these products has been studied in the air in the temperature range of 293–1273 K. Thermolysis and IR spectroscopy revealed a formation of rhamnolipid biocomplex between rhamnolipids and exopolysaccharide upon acidification of the culture fluid supernatant to pH = 3. Cellular polymer – polyhydroxyalkanoate – was identified by UV-Vis spectroscopy.

The IR spectroscopy and complex thermal analysis have been used to analyze the adsorption capacity of Transcarpathian clinoptilolite, both naturally occurring and activated, relative to water vapor.

The chemical compositions and properties of glass of different systems for the production of glass ionomer dental cements (GIC) were analyzed. For the synthesis of glass, the basic system 4SiO2–3Al2O3 – xNb2O5 – CaO with the content of Nb2O5 8.8 and 16.2% (wt.) is proposed. High-temperature technology and parameters of glass production for GIC are presented in the article. The properties of synthesized niobium-containing glass were determined and analyzed. The effect of niobium oxide on the crystallization ability of glass was determined by the method of differential thermal analysis.

Based on the complex thermal, titrimetric and UV/Vis spectral analyzes, the structure and the content of functional groups in the molecules of humic acids obtained from different raw materials – coprolite, peat and leonardite – were investigated. The thermal stability of the substances was investigated in the air in the temperature range 20-1000°C. It has been found that the content of the aliphatic component is predominant in humic acids obtained from different raw materials.