activation energy

The work is devoted to determining the features of the swelling kinetic patterns of polymer materials in contact with blended fuel containing fatty acid esters. Kinetic equations for predicting the behavior of polymer materials in contact with blended fuel at different temperatures were obtained. Peculiarities of the swelling kinetics of polymer materials with different chemical structures in blended diesel fuel were studied. It was found that the process proceeds in two stages for any temperature conditions.

Studied of co-gasification of heavy coal tars with lignite and walnut shell in the temperature ranged from  400 to 500 °С, the flow rate of oxidand (air) ranged from 0,0005 to  0,004 m3/min.  It is established that the weigth loss of the sample mixtures in the gasification process has a S-shaped. Mathematical and graphical dependences of the influence of oxidant flow rate on the values of reaction rate constants and activation energy of gasification of experimental mixtures were developed.

One of the main tasks of modern nanochemistry is the controlled synthesis of metal nanoparticles (MNPs) and in particular of silver (AgNPs). AgNPs have wide applicability in catalysis, electronics, sensors and biomedicine, which makes interest in this material. In the last decade, the "green" method of synthesizing nanoparticles of metals, which is includes minimizing of the use of toxic substances as reducing agents and based on the chemical reduction of Argentum ions and the stabilization of AgNPs by organic, non-toxic substances.

In Ukraine plant biomass from crop fields and forests is the dominant renewable energy source and it is suitable to replace fuels by producing bio-gas, bio-ethanol as well as solid bio-fuel. Tubes of Jerusalem artichoke are used as functional food ingredients such as inulin, fructose and oligofructose as well as bioactive ingredient sources for pharmaceutical and cosmetic applications.

One of the promising directions for production of advanced materials is creation of hybrid organic-inorganic nanocomposites that demonstrate not only the improved properties of organic matrix, but also the emergence of the new specific properties due to the presence of inorganic component. Hybrid organic-inorganic materials can be synthesized by sol-gel method as a result of sol-gel process involving organic-inorganic precursors. Nowadays sol-gel technique is considered as a simple and an ecologically friendly method of nanocomposite syntheses.

The kinetic investigations of phase formation processes in the mixture which contains BaO, Al2O3, Fe2O3  were carried out. The degree of conversion and the activation energy were calculated, the dependence of the reaction rate and the rate constant on reaction temperature was determined.

Kinetic peculiarities of the early stages of the processes of acid-catalyzed hydrolysis and condensation in sol-gel systems tetraethoxysilane (TEOS)–ethanol–water have been investigated by gas chromatography. Kinetic parameters of the process, evaluated using quantum-chemical calculations, satisfactorilly coincide with the ones determined experimentally.

Kinetic regularities of epoxy resins chemical modification by aliphatic and aromatic dibasic acids have been studied. The commercial dianic resins ED-20 and ED-24 were used as epoxy resins. Oxalic, malonic, succinic, sebacic, maleic, terephthalic and isophthalic acids were used as dibasic carboxylic acids. The effective rate constants and activation energies of the reactions between epoxy resin and acids by different nature have been calculated. The synthesis method for oligomers with epoxy and carboxy groups has been suggested.

The usage of fine grinded silicate glass as an active additive to Portland cement has been considered in order to substitute neat cement in the cement composition, just as it is in EN 197-1 European standard by the example of active mineral additives of natural and artificial origin.