Mechanochemical Phenomena in Polymers. II. The Effects of Initiators and Inhibitors of Radical Processes

1960 ◽  
Vol 33 (4) ◽  
pp. 946-952
Author(s):  
E. V. Reztsova ◽  
B. G. Lipkina ◽  
G. L. Slonimskiĭ
Keyword(s):  
Free Radicals ◽  
Fatigue Resistance ◽  
Substantial Effect ◽  
Chemical Bonds ◽  
Elastic Materials ◽  
Industrial Processing ◽  
Chain Processes ◽  
Radical Processes ◽  
Effect Of Inhibitors ◽  
Highly Elastic Materials

Abstract 1. The substantial effect of inhibitors and initiators of chain radical processes on the change in the properties of rubbers in milling, as well as on the resistance of vulcanizates to fatigue, has been shown. This indicates a mechanochemical mechanism of the processes occurring in processing polymers and of the fatigue of highly elastic materials (e.g., rubber vulcanizates). The act of mechanical scission of chemical bonds, with the formation of free radicals which initiate the secondary chain processes, rests on these processes. 2. The possibility has been shown of regulating the properties of polymers in the course of their industrial processing, and also of increasing the dynamic fatigue resistance of vulcanizates by incorporating small quantities of additives active in regard to free radicals.

Mechanochemical Phenomena in Polymers. II. The Effects of Initiators and Inhibitors of Chain Processes

1963 ◽  
Vol 36 (2) ◽  
pp. 480-487
Author(s):  
E. V. Reztsova ◽  
B. T. Kipkina ◽  
G. L. Slonimskii
Keyword(s):  
Free Radicals ◽  
Fatigue Resistance ◽  
Substantial Effect ◽  
Chemical Bonds ◽  
Chain Processes ◽  
Radical Processes ◽  
Effect Of Inhibitors ◽  
Dynamic Fatigue

Abstract 1. The substantial effect of inhibitors and initiators of chain radical processes on the change in the properties of rubbers in milling, as well as on the resistance of vulcanizates to fatigue, has been shown. This indicates a mechanochemical mechanism for processing of polymers and in the fatigue of elastomers. The act of mechanical scission of chemical bonds, with the formation of free radicals which initiate the secondary chain processes, rests on these processes. 2. The possibility has been shown of regulating the properties of polymers during processing, and also of increasing the dynamic fatigue resistance of vulcanizates by incorporating small quantities of additives active in regard to free radicals.

Mechanochemical Phenomena in Polymers. III. Strength of the Bond between Elements of Multiply Polymer Articles

1960 ◽  
Vol 33 (4) ◽  
pp. 953-958
Author(s):  
G. L. Slonimskiĭ ◽  
G. P. Drugova
Keyword(s):  
Free Radicals ◽  
Chemical Processes ◽  
Chemical Bonds ◽  
Mechanochemical Process ◽  
Vulcanized Rubber ◽  
Radical Processes

Abstract 1. The basis of the process of ply separation of multiply rubber articles under repeated deformations is fatigue of the material in the region of the joint of the plies, which is a mechanochemical process, as previously studied, consisting of the development of chain chemical processes initiated by free radicals which are formed in the mechanical scission of chemical bonds in the molecules. 2. By the addition of substances inhibiting chain radical processes to the polymer it is possible to raise considerably the strength of the bond between elements of multiply vulcanized rubber articles.

The strength of highly elastic materials

1967 ◽  
Vol 300 (1460) ◽  
pp. 108-119 ◽  
Keyword(s):  
Chemical Structure ◽  
Unit Area ◽  
Strength Properties ◽  
Polymer Chains ◽  
Chemical Bonds ◽  
Elastic Materials ◽  
Chemical Corrosion ◽  
Vulcanized Rubber ◽  
Theory And Experiment ◽  
Highly Elastic Materials

Under repeated stressing, cracks in a specimen of vulcanized rubber may propagate and lead to failure. It has been found, however, that below a critical severity of strain no propagation occurs in the absence of chemical corrosion. This severity defines a fatigue limit for repeated stressing below which the life can be virtually indefinite. It can be expressed as the energy per unit area required to produce new surface ( T 0 ), and is about 5 x 10 4 erg/cm 2 . In contrast with gross strength properties such as tear and tensile strength, T 0 does not correlate with the viscoelastic behaviour of the material and varies only relatively slightly with chemical structure. It is shown that T 0 can be calculated approximately by considering the energy required to rupture the polymer chains lying across the path of the crack. This energy is calculated from the strengths of the chemical bonds, secondary forces being ignored. Theory and experiment agree within a factor of 2. Reasons why T 0 and the gross strength properties are influenced by different aspects of the structure of the material are discussed.

Friction properties of highly elastic materials at high contact pressures

1973 ◽  
Vol 7 (1) ◽  
pp. 115-120
Author(s):  
G. M. Bartenev ◽  
V. V. Lavrent'ev ◽  
V. S. Voevodskii
Keyword(s):  
Elastic Materials ◽  
Contact Pressures ◽  
Highly Elastic Materials

Flow Phenomena in Rubber Samples

1950 ◽  
Vol 23 (1) ◽  
pp. 67-88
Author(s):  
Fritz Rössler
Keyword(s):  
Low Temperatures ◽  
Test Specimen ◽  
Room Temperature ◽  
Elastic Materials ◽  
Dead Weight ◽  
Point Change ◽  
Different Types ◽  
Flow Phenomena ◽  
High Degree ◽  
Highly Elastic Materials

Abstract A more extended investigation was made of the surprising flow phenomena which were found in an earlier study of rubber at low temperatures. The tensile apparatus was reconstructed so that a dead-weight load could be applied to the rubber test-specimen. Determinations of the dependence of the rate of flow on time of stressing, initial elongation, magnitude of the stress, and temperature showed that a simple law can be derived for expressing the flow phenomena. Yield point, change in color, and deterioration in physical properties, as well as the reversibility of these phenomena were investigated and are discussed. The phenomena of flow at room temperature are expressed by the same constants as at lower temperatures. Only the effective stress increases at low temperatures and only by this change does flow become perceptible. Different types of rubber were compared, and all showed approximately the same value for the flow constant. The essential characteristics of the flow phenomenon can be explained, on a basis of the theory of highly elastic materials, by their microliquid state of aggregation. This applies to the high degree of dependence of the mechanical properties of rubber on the temperature.

Oxidation-Reduction Systems for Initiation of Radical Processes. VI. Systems Involving Oxygen for Initiation of Oxidative Degradation of Polymers

1959 ◽  
Vol 32 (1) ◽  
pp. 231-243 ◽  
Author(s):  
E. I. Tinyakova ◽  
B. A. Dolgoplosk ◽  
V. N. Reĭkh
Keyword(s):  
Free Radicals ◽  
Low Temperatures ◽  
Oxidative Degradation ◽  
Chain Process ◽  
Iron Salts ◽  
Oxidation Reduction ◽  
A Chain ◽  
Radical Processes ◽  
Effective Source ◽  
Hydrocarbon Media

Abstract 1. The mechanism of action of various oxidation-reduction systems containing organic reducing agents, iron salts, and oxygen, is investigated, and it is shown that in hydrocarbon media these systems are an effective source of free radicals at low temperatures. 2. The possibility of utilization of these systems for initiation of a chain process of oxidative degradation of unsaturated and some saturated polymers, at low temperatures, is shown.

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