The Kinetics of High Elasticity in Synthetic Polymers

1942 ◽  
Vol 15 (3) ◽  
pp. 430-437
Author(s):  
R. F. Tuckett
Keyword(s):  
Molecular Structure ◽  
Physical Properties ◽  
Specific Heat ◽  
Elastic Properties ◽  
Volume Expansion ◽  
Synthetic Polymers ◽  
Dielectric Dispersion ◽  
High Elasticity ◽  
Cross Links ◽  
Kinetics Of

Abstract The simple Mark-Kuhn theory of high elasticity of rubber has been extended, on the basis of the work of Alexandrov and Lazurkin, to cover the elastic properties of other polymers. The chief principle invoked is that high elasticity is developed only when rotation of the main C—C chain in the polymer is comparatively free. The effect of molecular structure, plasticizer and cross-links on elastic properties has been indicated, and also a connection with other observed physical properties, such as volume expansion, dielectric dispersion and specific heat.

Relation between Molecular Weights and Physical Properties of Rubber Fractions

1941 ◽  
Vol 14 (3) ◽  
pp. 580-589 ◽  
Author(s):  
G. Gee ◽  
L. R. G. Treloar
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Physical Properties ◽  
High Molecular Weight ◽  
Elastic Properties ◽  
Elastic Material ◽  
Experimental Results ◽  
Molecular Weights ◽  
High Elasticity ◽  
Latex Rubber

Abstract As high elasticity is a property possessed only by substances of high molecular weight, it is of interest to enquire into the relation between the elastic properties of a highly elastic material such as rubber and its molecular weight. An investigation on these lines has been made possible through the work of Bloomfield and Farmer, who have succeeded in separating natural rubber into fractions having different average molecular weights. The more important physical properties of these fractions have been examined with the object of determining which of the properties are dependent on molecular weight and which are not. Fairly extensive observations were made on the fractions from latex rubber referred to as Nos. 2, 3 and 4 by Bloomfield and Farmer, and some less extensive observations were carried out on the less oxygenated portion of fraction No. 1 obtained from crepe rubber (called hereafter 1b) . Before considering these experimental results, and their relation to the molecular weights of the fractions, it will be necessary to refer briefly to the methods used for the molecular-weight determinations, and to discuss the significance of the figures obtained.

Vitrification of High Polymers in Periodic Deformation

1954 ◽  
Vol 27 (1) ◽  
pp. 12-15
Author(s):  
G. M. Bartenev
Keyword(s):  
Physical Properties ◽  
Elastic Properties ◽  
Liquid State ◽  
Amorphous Structure ◽  
Vitreous State ◽  
Linear Character ◽  
High Elasticity ◽  
Amorphous Structures ◽  
Heat Expansion ◽  
High Polymers

Abstract As is known, high polymers are readily supercooled and retain their amorphous structure below their crystallization points. Changes of the physical properties in the temperature range of crystallization are a linear function of temperature. When the temperature is lowered further, high polymers remain in their amorphous liquid state; this is indicated in particular by their retaining their high elastic properties below the crystallization temperature. However, with further decrease of temperature, the linear character of the changes of physical properties is no longer evident, and the latter undergo more or less abrupt anomalous changes. In particular, there is a change of the polymer from the amorphous-liquid state with high elasticity into a hard vitreous form, which, as is known, is not related to changes of the structure of high polymeric substances. Vitrified polymers, like amorphous liquids, possess amorphous structures. A number of investigators have found similar anomalies in the heat capacity, heat expansion, dielectric properties, and high elastic properties of various polymers during transition to the vitreous state.

AISI 3150

Alloy Digest ◽  
1963 ◽  
Vol 12 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Physical Properties ◽  
Tensile Properties ◽  
Nickel Alloy ◽  
Elastic Properties ◽  
Alloy Steel ◽  
Heat Treating ◽  
Great Depth ◽  
Medium Carbon ◽  
Steel Mills

Abstract AISI 3150 is a medium carbon, chromium-nickel alloy steel having great depth hardness, high elastic properties and excellent fatigue resistance and toughness. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on heat treating and machining. Filing Code: SA-143. Producer or source: Alloy steel mills and foundries.

Physical properties and reaction kinetics of CO2 absorption into unloaded and CO2 loaded viscous monoethanolamine (MEA) solution

2021 ◽  
Vol 329 ◽  
pp. 115569
Author(s):  
Rouzbeh Ramezani ◽  
Ida M. Bernhardsen ◽  
Renzo Di Felice ◽  
Hanna K. Knuutila
Keyword(s):  
Physical Properties ◽  
Reaction Kinetics ◽  
Co2 Absorption ◽  
Kinetics Of

scholarly journals Physical properties and water absorption kinetics of three varieties of Mucuna beans

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ajibola B. Oyedeji ◽  
Olajide P. Sobukola ◽  
Ezekiel Green ◽  
Oluwafemi A. Adebo
Keyword(s):  
Physical Properties ◽  
Water Absorption ◽  
Rate Constant ◽  
Geometric Mean ◽  
Seed Mass ◽  
Activation Energies ◽  
Mucuna Pruriens ◽  
Absorption Kinetics ◽  
Kinetics Of ◽  
Soaking Temperature

AbstractThe physical properties and water absorption kinetics of three varieties of Mucuna beans (Mucuna pruriens, Mucuna rajada and Mucuna veracruz) were determined in this study. Physical properties including length, width, thickness, geometric mean diameter, sphericity, porosity, bulk density, area, volume and one thousand seed mass were calculated while hydration kinetics was studied by soaking Mucuna beans in water at 30 °C, 40 °C and 50 °C and measuring water uptake at 9 h interval. Peleg’s equation was used to model the hydration characteristics and Arrhenius equation was used to describe the effect of temperature on Peleg’s rate constant k1 and to obtain the activation energies for soaking. Significant variations were observed in almost all the physical properties of the different varieties, however, there were no significant differences (p < 0.05) in their thicknesses and bulk densities. The effectiveness of fit of Peleg’s model (R2) increased with increase in soaking temperature. Peleg’s rate constant k1 decreased with increase in soaking temperature while k2 increased with temperature increase. Activation energies of Mucuna pruriens, Mucuna rajada and Mucuna veracruz were 1613.24 kJ/mol, 747.95 kJ/mol and 2743.64 kJ/mol, respectively. This study provides useful information about the properties of three varieties of Mucuna beans that could be of importance to processors and engineers for process design and optimization.

Vulcanization of Elastomers. 23. The Chemical Kinetics of Vulcanization Reactions and The Physical Properties of The Vulcanizates. I

1960 ◽  
Vol 33 (2) ◽  
pp. 335-341
Author(s):  
Walter Scheele ◽  
Karl-Heinz Hillmer
Keyword(s):  
Activation Energy ◽  
Physical Properties ◽  
Chemical Kinetics ◽  
Kcal Mole ◽  
First Order ◽  
Equilibrium Swelling ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization ◽  
Limiting Value ◽  
Good Agreement

Abstract As a complement to earlier investigations, and in order to examine more closely the connection between the chemical kinetics and the changes with vulcanization time of the physical properties in the case of vulcanization reactions, we used thiuram vulcanizations as an example, and concerned ourselves with the dependence of stress values (moduli) at different degrees of elongation and different vulcanization temperatures. We found: 1. Stress values attain a limiting value, dependent on the degree of elongation, but independent of the vulcanization temperature at constant elongation. 2. The rise in stress values with the vulcanization time is characterized by an initial delay, which, however, is practically nonexistent at higher temperatures. 3. The kinetics of the increase in stress values with vulcanization time are both qualitatively and quantitatively in accord with the dependence of the reciprocal equilibrium swelling on the vulcanization time; both processes, after a retardation, go according to the first order law and at the same rate. 4. From the temperature dependence of the rate constants of reciprocal equilibrium swelling, as well as of the increase in stress, an activation energy of 22 kcal/mole can be calculated, in good agreement with the activation energy of dithiocarbamate formation in thiuram vulcanizations.

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