Search

Polymer-polymer composites based on polyaniline and polymethacrylic acid were obtained. The electrical conductivity, heat resistance, X-ray spectra of the obtained composites were studied. Intermolecular hydrogen bonds are formed between the components of the composite. Increasing the content of polymethacrylic acid in the composite increases its heat resistance. The process of thermal destruction of polyaniline, polymethacrylic acid and composite is complex and takes place in several stages. The conducted quantum chemical calculations confirm the conclusion about the formation of intermolecular hydrogen bonds between the components of the composite. [ABSTRACT FROM AUTHOR]

Polymer-polymer composites based on polyaniline and polymethacrylic acid were obtained. The electrical conductivity, heat resistance, X-ray spectra of the obtained composites were studied. Intermolecular hydrogen bonds are formed between the components of the composite. Increasing the content of polymethacrylic acid in the composite increases its heat resistance. The process of thermal destruction of polyaniline, polymethacrylic acid and composite is complex and takes place in several stages. The conducted quantum chemical calculations confirm the conclusion about the formation of intermolecular hydrogen bonds between the components of the composite. [ABSTRACT FROM AUTHOR]

Are obtained polymer-polymer composites based on polyaniline and water-soluble polymers - polyvinyl alcohol, polymethacrylic acid and copolymer of styrene with maleic anhydride. Investigation of thermomechanical properties and X-ray and FTIR spectra showed that intermolecular hydrogen bonds are formed between the conductive polymer and a water-soluble polymer. Constructed quantum-chemical models of composites were proposed. The energy of hydrogen bonds is found. [ABSTRACT FROM AUTHOR]

The effects of dispersed oxides Fe2O3, Cr2O3, α-PbO, β-PbO, PbO2, SiO2 on the processes of radical polymerization of styrene are studied. It is shown that the dispersed oxides affect the polymerization rate and the response of the thermal decomposition of radical initiators. Peroxides are adsorbed on the surface of mineral oxides and decomposed into free radicals. On the surface of SiO2 and Cr2O3, a heterolytic decomposition of peroxides takes place. The oxide introduced into the polymerization system reduces the molecular weight of the polymer that forms under these conditions. The degrees of grafting macromolecules to the surface of oxides were found. [ABSTRACT FROM AUTHOR]

The reaction of sulfoxides with peroxy acids in various organic media was studied. The reaction mechanism involves the rapid formation of a sulfoxide-–peroxy acid intermediate which decomposes in the second stage to form carboxylic acid and the corresponding sulfone. The second stage is the rate-limiting step. The reaction medium significantly affects the rate of oxidation. The calculated activation parameters of the oxidation process indicate a compensation effect in the investigated reaction. Correlations between the main physicochemical parameters of solvents and the effective rate constants (k) of dimethyl sulfoxide oxidation with peroxy acids were found. Depending on the reaction conditions, the main factors affecting the k values are specific and nonspecific solvation of the reactants and structural factors. [ABSTRACT FROM AUTHOR]

The kinetics of thermal decomposition of didecanoyl diperoxyadipate in different organic solvents have been studied. The primary homolytic dissociation of the peroxide bond (O-O) is accompanied by secondary induced chain decomposition processes. The reaction medium affects both the rate of primary homolytic decomposition and secondary decomposition processes. Correlation equations have been proposed for the rate constants of the reactions under study and physicochemical parameters of the solvents. [ABSTRACT FROM AUTHOR]

Thermal decomposition of peroxydecanoic acid has been investigated in various organic solvents. The reaction medium significantly affects the rate of peroxydecanoic acid thermal decomposition. It has been shown that primary homolytic decomposition of peroxy group is followed by induced radical chain decomposition reactions. The solvent nature influences both primary homolytic decomposition and secondary induced reactions. The correlation equations relating kinetic parameters of peroxydecanoic acid thermolysis and basic solvent properties have been derived. [ABSTRACT FROM AUTHOR]

Composites based on polyaniline and nanostructured zinc oxide were synthesized by mechanical mixing and the method ofin situpolymerization and their physicochemical properties were studied. The electrical conductivity, surface structure and morphology of composites have been investigated. It is shown that the method of synthesis and quantity of filler affects the morphology and physicochemical properties of composite materials. An addition of various quantities of mineral filler to composite allows controlling conductivity of obtained materials. XRD-analysis of composite materials synthesized byin situpolymerization confirms the interaction of the components of the composite. [ABSTRACT FROM AUTHOR]

Reaction of epoxidation of α-pinene and Δ-carene with peroxydecanoic acid in various organic solvents was studied. Effective activation energies of oxidation of α-pinene and Δ-carene with peroxydecanoic acid in various media are evaluated. It is shown that reaction medium significantly affects the rate of the process. Correlation dependences connecting the rate of epoxidation with main parameters of solvents are found. [ABSTRACT FROM AUTHOR]

The adsorption of oligo(sebacoyl peroxide) on Aerosil and MgO and benzoyl peroxide on Fe 2O 3, Cr 2O 3, and V 2O 5 has been studied. It has been established that peroxide adsorption on the considered adsorbents is described by the Langmuir equation. Benzoyl-peroxide adsorption increases in the series Fe 2O 3 < Cr 2O 3 < V 2O 5. The process of thermal decomposition of peroxides in the presence of the listed adsorbents has been studied. The overall reaction of peroxide decomposition comprises two components, i.e., the decomposition processes occurring in a solution and on an adsorbent surface. Kinetic and activation parameters of the thermal-decomposition reactions in the solutions and on the surfaces have been determined. [ABSTRACT FROM AUTHOR]

Features of styrene polymerization in the presens of disperse iron oxide. It was shown, the iron oxide surface takes part in the initiation polymerization reaction and termination polymer chains. Degrees of grafting of polysterene macromolecules to the mineral surface were determinate. The equation of polymerization rate in the presens of Fe2O3 was proposed. [ABSTRACT FROM AUTHOR]

The thermal decomposition reactions of aliphatic peroxy acids containing from 8 to 16 carbon atoms in a molecule were studied. It was found that the carbon radical length had no effect on the thermal stability of peroxide groups. The apparent rate constants of thermolysis of peroxydecanoic acid in various solvents and the activation energies of the test reaction were found. The thermal degradation of peroxy acids involved secondary reactions of induced chain degradation in addition to the primary homolysis of the peroxide group. The rate constants of induced chain degradation were found. [ABSTRACT FROM AUTHOR]

Influence of lead oxides on styrene polymerization, induced with benzoyl peroxide (BP) and tert-butyl hidroperoxide of (TBHP) was studied. It was shown, the lead oxide surface takes part in the initiation polymerization reaction of styrene if TBHP is used as initiator , but BP causes polymerization mainly in solution. Energies of activating of styrene polymerization, which was initiated with TBHP, reduces with growing of lead oxide contain in the system. Molecular weigh studying degrees of molecular grafting to the mineral surface and polydispersity of polystyrene testifies about the participation of addector in the reaction of initiation and termination. [ABSTRACT FROM AUTHOR]

The catalytic decomposition of peroxy acids is studied in various solvents in the presence of manganese, cobalt, chromium, nickel, and copper acetates and cerium benzoate. The catalytic activity of the salts in peroxy acid decomposition decreases in the order Mn2+ > Co2+ > Ce3+ > Cr3+ > Ni2+ > Cu2+. The apparent activation energies of the catalytic decomposition of peroxydecanoic acid range between 45.9 and 88.0 kJ/mol. The reaction medium has an effect both on the apparent rate constant and on the activation energy of the reaction. The reaction mechanism includes the fast formation of a catalyst-peroxy acid intermediate complex, which decomposes to release a catalyst molecule and forms the reaction products. The oxidation state of the metal ion of the catalyst can change. The introduction of compounds capable of forming complexes with metal ions of the catalyst substantially slows down the catalytic decomposition. [ABSTRACT FROM AUTHOR]

The influence of klynoptilolite on vinyl monomer polymerization has been studied. Polymerization initiation with klynoptilolite, modified with Fe3+, Fe2+, Cr3+, Ni2+ metals, was passed according to redox reaction of organic peroxides with mineral surface. Part of polymer forms in the solution. Degree of links of polymer with mineral surface has been found. Two possible kation and radical mechanisms of styrene polymerization in the presence of unmodified klinoptilolite were suggested. [ABSTRACT FROM AUTHOR]

We present a complete description of Lie symmetries for the nonlinear diffusive Lotka-Volterra system. The results are used for the construction of exact solutions of the Lotka-Volterra system, which, in turn, are used for solving the corresponding nonlinear boundary-value problems with zero Neumann conditions. The analytic results are compared with the results of computation based on the finite-element method. We conclude that the obtained exact solutions play an important role in solving Neumann boundary-value problems for the Lotka-Volterra system. [ABSTRACT FROM AUTHOR]

We study the influence of temperature of a working medium and loading frequency on the contact fatigue of 20KhN3A and ShKh15 steels in oil and in a 3% NaCl aqueous solution. It is shown that, as the loading frequency increases, the contact fatigue of steels increases in a 3% NaCl aqueous solution but does not change in oil. At the same time, as temperature increases, the contact fatigue decreases in a 3% NaCl aqueous solution but remains almost constant in oil. It is shown that the outlined behaviors of the analyzed steels is explained by the action of the components of working media and their concentrations in the surface layers in the course of the tests. [ABSTRACT FROM AUTHOR]

The results of the study of the length of the prenatal period of ontogenesis of 51 Ukrainian Red Dairy breed tribal cows are presented, and the relationship of this trait with the rate of growth of the organism in the postnatal period (at birth, at 6, 12 and 18 months) and dairy productivity for the first lactation are investigated. Also, at different stages of the prenatal period of ontogeny the dynamics of the mass of 66 fetus and some parenchymatous organs (liver, spleen, thymus) selected by anatomical preparation are determined. The aim of the research was to establish the possibility of predicting dairy productivity of Ukrainian Red Dairy breed cows over the length of the prenatal period and the effect of this period on the postnatal growth rate of the organism, and also to ascertain the existence of a regularity between the increase in fetus mass and the development of certain hemopoiesis organs at different stages of prenatal development. Laboratory animals were divided into three groups, depending on length of their prenatal period: less than 277 days-reduced (group I), 277-283 - medium (group II) and more than 283 days - extended period (group III). For 305 days of the first lactation, the advantage over milk yield, milk fat yield and milk protein belongs to animals with shortened duration of the prenatal period of ontogenesis in comparison with contemporaries who had an extended period with a statistically significant difference (P < 0.05). A further study in the short term may be a study of the relationship between the duration of the prenatal period and the rate of fetal growth with the subsequent forming of the physique, and in the long term turning into the study of the relationship between the duration of the prenatal period and the rate of fetal growth with a duration of productive use and lifelong productivity. [ABSTRACT FROM AUTHOR]