scholarly journals MECHANODESTRUCTION OF ISOPRENE RUBBER. PART 3. KINETICS OF OXIDATIVE DESTRUCTION

2021 ◽  
Vol 80 (5) ◽  
pp. 230-234
Author(s):  
В. Дорожкин ◽  
Е. Мохнаткина ◽  
Д. Земский ◽  
А. Валиев
Keyword(s):  
Activation Energy ◽  
Oxygen Diffusion ◽  
Effective Activation Energy ◽  
Effective Activation ◽  
Oxidative Destruction ◽  
Absolute Value ◽  
Rubber Part ◽  
Kinetics Of ◽  
Isoprene Rubber ◽  
Kinetic Features

Continuation of studies of changes in molecular parameters, in particular, the molecular weight (MM) during the plasticization (P) of SKI-3 isoprene rubber. The kinetics of oxidative destruction (OD) in the temperature range (T) 30-130 °C and time (t) 30–600 s were studied in detail. Plasticization of rubber, as before, was carried out in a laboratory rubber mixer of the company «NFM», and gel chromatographic studies were carried out on a gel chromatograph of the company «Waters». The speed constant OD K0 decreases in absolute value with a decrease in T and an increase in t. The calculated effective activation energy of OD Eeff decreases from 24,4 to 13 kJ/mol in the studied t range. The influence of the oxygen diffusion process on the kinetic features of the OD of SKI-3 at Р is pointed out.

Mechanodestruction of Isoprene Rubber. Part 1. Process Kinetics

2021 ◽  
Vol 80 (3) ◽  
pp. 118-122
Author(s):  
V.P. Dorozhkin ◽  
◽  
E.G. Mokhnatkina ◽  
D.N. Zemsky ◽  
A.D. Valiev ◽  
...  
Keyword(s):  
Experimental Data ◽  
Molecular Mass ◽  
Rate Constants ◽  
Oxidative Destruction ◽  
Process Kinetics ◽  
Mass Fractions ◽  
Rubber Part ◽  
Kinetics Of ◽  
Selection Of ◽  
Isoprene Rubber

A method is proposed that allows us to obtain the values of the rate constants (CR) of the processes of mechanodestruction (mechanical cracking) of kм, oxidative destruction of kо, and recombination of kр macromolecules, as well as the mass fractions of the corresponding fractions of φм, φо, and φр,r involved in the plasticization process (P) of SKI-3 isoprene rubber. The method is based on the selection of the values of these parameters that correspond to the previously obtained experimental data, using the previously obtained recurrent equations and a specially developed program. The dependences of the CR on the time P at 30oC are obtained, which allows us to describe the kinetics of the processes accompanying P at this temperature, and the changes in molecular mass (MM) in this process. It is shown that constant values of CR are established at large times of P. Refined explanations of the nature of the kinetics of the CR change at P are proposed. The MM value of SKI-3 macromolecules that have not undergone destruction is calculated, depending on the time of plasticization.

scholarly journals SYNTHESIS OF THALLIUM SULPHATE IN A SULFURIC ACID SOLUTION AT POLARIZATION BY CURRENT

2021 ◽  
pp. 47-54
Author(s):  
A. B. Baeshov ◽  
G.T. Sarbayeva ◽  
E. Zh. Tuleshova ◽  
M. A. Ozler ◽  
M.T. Sarbayeva
Keyword(s):  
Activation Energy ◽  
Sulfuric Acid ◽  
Effective Activation Energy ◽  
Research Work ◽  
Effective Activation ◽  
Oxidation Reduction ◽  
Density Concentration ◽  
The One ◽  
The Impact ◽  
Kinetics Of

Nowadays, the one of the actual problems is the recycling of metal waste and its provision to consumers. However, it is known that there are a number of difficulties with the recycling of thallium waste. By using new recycling methods, it's possible to increase thallium resources and lower prices for thallium-derived products. Therefore, some work was carried out to extract its compounds from thallium waste by studying the electrochemical properties of thallium in our research work. The experimental results showed that thallium electrodes dissolve in an aqueous solution of sulfuric acid under alternating current polarization with the formation of thallium (I) sulfate. In this work, the kinetics of electrochemical oxidation-reduction of thallium in aqueous solutions of sulfuric acid is studied by potentiometry. To characterize the mechanism of thallium electrooxidation, the following parameters were calculated: the order of the reaction and the effective activation energy of the process. The impact of electrolysis modes: current density, concentration and temperature of the electrolyte on the dimensional charac-teristics of the obtained thallium (I) sulfate was investigated.

The Kinetics of Excitonic Luminescence in Mixed Silver Halides

1994 ◽  
Vol 348 ◽  
Author(s):  
E. Kotomin ◽  
D. Millers ◽  
L. Grigorjeva ◽  
R. Eglitis
Keyword(s):  
Activation Energy ◽  
Electron Beam ◽  
Effective Activation Energy ◽  
Theoretical Treatment ◽  
Effective Activation ◽  
Silver Halides ◽  
Pulsed Electron Beam ◽  
Luminescence Kinetics ◽  
Kinetics Of ◽  
Excitonic Luminescence

ABSTRACTTwo kinds of luminescence (excitonic luminescence and excitonic molecule luminescence) were investigated for solid solutions AgBr1-xClx after pulsed electron beam and N2 laser irradiation. Careful theoretical treatment of a set of experimental excitonic luminescence kinetics is presented. It is shown that the effective activation energy of Agoi migration is a linear function of the composition x. The narrow peak of the excitonic molecule luminescence shifts from 2.66ev in pure AgBr towards higher energies as x increases.

MAGNETIC RESISTIVITY IN Bi2Sr2Ca(Cu1-xCox)2Od EPITAXIAL THIN FILMS

2007 ◽  
Vol 21 (01) ◽  
pp. 127-132
Author(s):  
T. R. YANG ◽  
G. ILONCA ◽  
V. TOMA ◽  
P. BALINT ◽  
M. BODEA
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Activation Energy ◽  
Glass Transition ◽  
Effective Activation Energy ◽  
Epitaxial Thin Films ◽  
Effective Activation ◽  
High Quality ◽  
Plastic Deformations ◽  
Magnetic Resistivity

The scaling behavior of the effective activation energy of high-quality epitaxial c-oriented Bi 2 Sr 2 Ca ( Cu 1-x Co x)2 O d thin films with 0≤x ≤0.025 has been studied as a function of temperature and magnetic field. For all samples, the effective activation energy scales as U(T, μoH)=Uo(1-T/T c )mHn with exponent m=1.25±0.03, n=-1/2 and the field scaling 1/μoH and -UμoH for thick films and ultra thin films, respectively. The results are discussed taking into account of the influence of the Co substitution with a model in which U(T, H) arises from plastic deformations of the viscous flux liquid above the vortex-glass transition temperature.

Correlation between effective activation energy and pre-exponential factor for diffusion in bulk metallic glasses

1999 ◽  
Vol 14 (8) ◽  
pp. 3200-3203 ◽  
Author(s):  
S. K. Sharma ◽  
F. Faupel
Keyword(s):  
Activation Energy ◽  
Metallic Glasses ◽  
Effective Activation Energy ◽  
Bulk Metallic Glasses ◽  
Supercooled Liquid ◽  
The Novel ◽  
Effective Activation ◽  
Exponential Factor ◽  
Liquid States ◽  
Fitting Parameters

The values of effective activation energy (Q) and pre-exponential factor (D0) reported in the literature for diffusion in the novel bulk metallic glasses, both in the glassy and the deeply supercooled liquid regions, are found to follow the same correlation as reported earlier in conventional metallic glasses, namely D0 = A exp(Q/B), where A and B are fitting parameters with values A = 4.8 × 10−19 m2 s−1 and B = 0.056 eV atom−1. A possible explanation for the observed values of A and B is given by combining an activation energy and a free volume term. The interpretation favors a cooperative mechanism for diffusion in the glassy and deeply supercooled liquid states.

MAGNETORESISTIVITY PROPERTIES AND EFFECTIVE ACTIVATION ENERGY IN YBa2Cu3O7-ρ SUPERCONDUCTING THIN FILM

2006 ◽  
Vol 20 (29) ◽  
pp. 1847-1852
Author(s):  
ALI IHSAN DEMIREL ◽  
SALIM ORAK
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Activation Energy ◽  
Applied Field ◽  
Effective Activation Energy ◽  
Creep Process ◽  
Two Dimensional ◽  
Effective Activation ◽  
Exponential Behavior ◽  
Superconducting Thin Film

The resistive properties and activation energy of YBa 2 Cu 3 O 7-ρ ( YBCO ) superconducting materials change in magnetic field. It is explained that magnetoresistive behavior in terms of the presence of two-dimensional vortices being pinned effectively when they are perpendicular to the CuO 2 planes and an exponential behavior of the activation energy versus the applied field was obtained. The resulting activation energies ranging from 1 to 5 Tesla were attributed to inter-granular flux creep process.

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