A model for producing polymer stabilizers of composites with a given macromolecule composition

An attempt has been made to obtain a working technological formula that regulates the addition of comonomer over time, which ensures the synthesis of a copolymer macromolecule with a constant composition and, accordingly, with predicted properties of both the copolymer and its modified porous composite materials. Mathematical modeling is based on the theory of the kinetics of copolymerization, which takes into account the reactivity of monomers by means of copolymerization constants of reacting comonomers. The starting base was the kinetics of the copolymerization of two comonomers, significantly differing in their reactivity, which required a sequential, stepwise supply of a less reactive monomer to the reaction medium with a more active monomer. This technological technique contributes to maintaining the constancy of the initial ratio of comonomers and, accordingly, the synthesis of a copolymer with a constant composition, structure and properties. The dependence of the sequence of supply of comonomer to the reaction medium required the introduction of a generalized effective binary copolymerization rate coefficient. To find the generalized coefficient of the copolymerization rate, the operation of logarithm was performed and the current expression of the dependence of the concentration change of the more active monomer in time in a linear form was translated. This mathematical technique made it possible to use software to process reference information to obtain the necessary coefficients for the working formula. As a result of mathematical modeling using the basic principles of binary copolymerization, the law of effective masses, and the least squares method, a working formula is obtained that allows one to regulate the given introduction of a less active monomer into the reaction medium in time. The model is analyzed using background information, the basic concepts of binary copolymerization and can be used in technological calculations when producing copolymers with specified characteristics in composition and structure.

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On the Human Infectious Disease Covid-19 Protective Clothing

International Journal of Infectious Diseases and Research ◽

10.47485/2693-2326.1001 ◽

2020 ◽

Keyword(s):

Mathematical Modeling ◽

Infectious Disease ◽

Heat Conduction ◽

Temperature Distribution ◽

Protective Clothing ◽

Least Squares Method ◽

Skin Layer ◽

Distribution Model ◽

The Given ◽

Human Infectious Disease

The temperature distribution and thickness design of the human infectious disease COVID-19 protective clothing are studied in this paper. Based on the data provided by China mathematical modeling competition in 2018. We establish the temperature distribution model and skin layer heat conduction and burn model. The interface continuous conditional difference method, differential iterative method, least squares method and the chasing method are used to solve the given temperature distribution on the the human infectious disease COVID-19 protective clothing in the environment, and analyze the human infectious disease COVID-19 protective clothing meeting the actual needs.

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Kinetics of catalytic conversion of methanol at higher pressures

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19803402 ◽

1980 ◽

Vol 45 (12) ◽

pp. 3402-3407 ◽

Cited By ~ 26

Author(s):

Jaroslav Bartoň ◽

Vladimír Pour

Keyword(s):

Low Temperature ◽

Reaction Kinetics ◽

Water Vapour ◽

Kinetic Data ◽

Catalytic Conversion ◽

The Given ◽

Kinetics Of

The course of the conversion of methanol with water vapour was followed on a low-temperature Cu-Zn-Cr-Al catalyst at pressures of 0.2 and 0.6 MPa. The kinetic data were evaluated together with those obtained at 0.1 MPa and the following equation for the reaction kinetics at the given conditions was derived: r = [p(CH3OH)p(H2O)]0.5[p(H2)]-1.3.

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Polymer structure and catalytic activity of ion exchangers

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19811577 ◽

1981 ◽

Vol 46 (7) ◽

pp. 1577-1587 ◽

Cited By ~ 8

Author(s):

Karel Jeřábek

Keyword(s):

Catalytic Activity ◽

Ethyl Acetate ◽

Active Sites ◽

Crosslinking Agent ◽

Reaction Medium ◽

Polymer Structure ◽

Local Concentration ◽

Ion Exchangers ◽

Styrene Divinylbenzene ◽

Kinetics Of

Catalytic activity of ion exchangers prepared by partial sulphonation of styrene-divinylbenzene copolymers in reesterifications of ethyl acetate by methanol and propanol, hydrolysis of ethyl acetate and in synthesis of bisphenol A has been compared with data on polymer structure of these catalysts and with distribution of the crosslinking agent, divinylbenzene, calculated from literature data on kinetics of copolymerisation of styrene with divinylbenzene. It was found that the polymer structure of ion exchangers influences catalytic activity predominantly by changing the local concentration of acid active sites. The results obtained indicated that the effect of transport phenomena on the rate of catalytic reactions does not depend on the degree of swelling of the ion exchangers in reaction medium but it is mainly dependent on the relative affinity of reaction components to the acid groups or to the polymer skeleton.

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Thermodynamic and detailed kinetic study of the formation of orthophthalaldehyde-agmatine complex by fluorescence intensities

Journal of Analytical Science & Technology ◽

10.1186/s40543-020-00238-2 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Khémesse Kital ◽

Moumouny Traoré ◽

Diégane Sarr ◽

Moussa Mbaye ◽

Mame Diabou Gaye Seye ◽

...

Keyword(s):

Complex Formation ◽

Thermodynamic Parameters ◽

Initial Rate ◽

Reaction Medium ◽

Standard Entropy ◽

Step Size ◽

Formation Reaction ◽

Different Temperatures ◽

Kinetics Of ◽

Complex Formation Process

Abstract The aim of this work is to determine the thermodynamic parameters and the kinetics of complex formation between orthophthalaldehyde (OPA) and agmatine (AGM) in an alkaline medium (pH 13). Firstly, the association constant (Ka) between orthophthalaldehyde and agmatine was determined at different temperatures (between 298 K and 338 K) with a step size of 10 K. Secondly, the thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°),and Gibbs energy (∆G) were calculated, where a positive value of ΔH° (+45.50 kJ/mol) was found, which shows that the reaction is endothermic. In addition, the low value of ΔS°(+0.24 kJ/mol) indicates a slight increase in the disorder in the reaction medium. Furthermore, the negative values of ΔG between −35.62 kJ/mol and −26.02 kJ/mol show that the complex formation process is spontaneous. Finally, the parameters of the kinetics of the reaction between OPA and AGM were determined as follows: when the initial concentration of AGM (5 × 10−6 M) is equal to that of the OPA, the results show that the reaction follows an overall 1.5 order kinetics with an initial rate of 5.1 × 10−7Mmin−1 and a half-life of 8.12 min. The partial order found in relation to the AGM is 0.8. This work shows that the excess of OPA accelerates the formation reaction of the complex.

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The Influence of High- and Low-molecular-weight Inhibitors on Dissolution Kinetics of Hydroxyapatite and Human Enamel in Lactate Buffers: A Constant Composition Study

Journal of Dental Research ◽

10.1177/00220345880670121001 ◽

1988 ◽

Vol 67 (12) ◽

pp. 1493-1498 ◽

Cited By ~ 7

Author(s):

J.A. Budz ◽

M. Lo Re ◽

G.H. Nancollas

Keyword(s):

Molecular Weight ◽

Dissolution Kinetics ◽

Low Molecular Weight ◽

Constant Composition ◽

Human Enamel ◽

Composition Study ◽

Kinetics Of

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MATHEMATICAL MODELING TIME INHOMOGENEOUS KINETICS OF POLYMERIZATION

Mathematical Methods in Technologies and Technics ◽

10.52348/2712-8873_mmtt_2021_1_106 ◽

2021 ◽

pp. 106-110

Author(s):

S.E. Zakiev ◽

Yu.P. Kvurt

Keyword(s):

Mathematical Modeling ◽

Kinetics Of Polymerization ◽

Kinetics Of

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Influence of High-Calcium Ash Composition on the Composite Binders’ Properties

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.316.1019 ◽

2021 ◽

Vol 316 ◽

pp. 1019-1024

Author(s):

O. A. Ignatova ◽

A. A. Dyatchina

Keyword(s):

Mechanical Properties ◽

Chemical Composition ◽

Cement Stone ◽

Normal Density ◽

Fine Aggregate ◽

Equivalent Amount ◽

High Calcium ◽

Composition Structure ◽

Kinetics Of ◽

Positive Effect

The paper presents the studies’ results of chemical composition, structure, and physico-mechanical properties of high-calcium ashes from the Kansk-Achinsk coals (2017-2019 selection). It was found that ash has a complex poly-mineral composition and contains hydraulically active minerals and oxides of СаОfr, β-C2S, CA, C3A, C4AF, C2F, CaSO4. According to the content of CaOfr, MgO does not meet standards’ requirements. The uniformity of the volume change is maintained by the composition with 50% of cement. The structure and hardening kinetics of ash and ash-cement stone compositions, obtained from the test of normal density, were analyzed. It was established that the hardening of compositions with ash from the Kansk-Achinsk coals was largely influenced by ash minerals. An equivalent amount of cement in composite binders cannot be replaced. In order to obtain a positive effect, compositions with ash instead cement of no more than 30% and a part of fine aggregate, without exceeding the ratio of ash: cement = 1: 1, should be used.

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Study of Molten Salt Corrosion of Superni-75 using Termogravimetric Technique

Journal of Naval Architecture and Marine Engineering ◽

10.3329/jname.v3i2.922 ◽

1970 ◽

Vol 3 (2) ◽

pp. 77-82 ◽

Cited By ~ 5

Author(s):

TS Sidhu ◽

S Prakash ◽

RD Agrawal

Keyword(s):

Corrosion Resistance ◽

Molten Salt ◽

Hot Corrosion ◽

Corrosion Behaviour ◽

Thick Layer ◽

X Ray Diffraction ◽

Salt Corrosion ◽

Marine Engineering ◽

The Given ◽

Kinetics Of

The present study aims to evaluate the hot corrosion behaviour of the Ni-based alloy Superni- 75 in the molten salt environment of Na2SO-60%V2O5 at 900°C under cyclic conditions. The thermogravimetric technique was used to establish the kinetics of corrosion. X-ray diffraction, scanning electron microscopy/energy-dispersive analysis and electron probe microanalysis techniques were used to analyse the corrosion products. Superni-75 has successfully provided the hot corrosion resistance to the given molten salt environment. The hot corrosion resistance of the Superni-75 has been attributed to the formation of uniform, homogeneous and adherent thick layer of the scale consisting mainly of oxides of nickel and chromium, and refractory Ni(VO3)2. These oxides and refractory nickel vanadates have blocked the penetration of oxygen and other corrosive species to the substrate. Keywords: Hot corrosion, nickel-based alloy, superalloy, molten salt environment DOI: 10.3329/jname.v3i2.922 Journal of Naval Architecture and Marine Engineering 3(2006) 77-82

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