Vulcanization of Rubber with Aminomercaptotriazines

1970 ◽  
Vol 43 (5) ◽  
pp. 1194-1214 ◽  
Author(s):  
H. Westlinning
Keyword(s):  
Fatigue Strength ◽  
Natural Rubber ◽  
Elemental Sulfur ◽  
Dynamic Deformation ◽  
New Class ◽  
High Fatigue ◽  
High Yields ◽  
Natural Rubber Vulcanizates ◽  
Kinetics Of ◽  
High Processing

Abstract Aminomercaptotriazines are a new class of accelerators for rubber vulcanization. The kinetics of the vulcanization reaction and the yield of crosslinks depend strongly on the molecular structure of the accelerators. The vulcanization is highly resistant to reversion which is demonstrated by a smaller increase in heat generation under dynamic deformation as well as by higher vulcanization temperatures and longer vulcanization times. In natural rubber and synthetic polyisoprenes aminomercaptodisulfides produce high yields of crosslinks combined with high processing safety. Fatigue strength of natural rubber vulcanizates is considerably enhanced by air aging. In blends of NR and SBR with BR, sulfenamides of dimercaptotriazines produce a very stable vulcanizate combined with good processing safety. Rate of cure can be increased by combination with a mercaptan. With polydisulfides SBR can be crosslinked without elemental sulfur at all. The vulcanizates have a high fatigue strength and a high hysteresis.

Kinetics of Crosslinking and Network Changes in Natural Rubber Vulcanizates with a Dithiodimorpholine Based Accelerator System

1980 ◽  
Vol 53 (5) ◽  
pp. 1015-1022 ◽  
Author(s):  
A. K. Bhowmick ◽  
S. K. De
Keyword(s):  
Natural Rubber ◽  
Rate Constants ◽  
Crosslink Density ◽  
Curing Temperature ◽  
Side Reactions ◽  
Filler Surface ◽  
Natural Rubber Vulcanizates ◽  
Kinetics Of ◽  
Accelerator System

Abstract Kinetics of crosslinking and network changes in unfilled and filled natural rubber vulcanizates with a dithiodimorpholine based accelerator system have been studied at 150° and 180°C. Results show that addition of HAF black enhances the polysulfidic crosslinks as well as the total crosslinks. This has been explained with the help of Coran's model wherein HAK black increases the rate constants. It is likely that the filler surface prevents desulfuration and undesirable side reactions involving the crosslink precursors. Increase of curing temperature by 30°C lowers the total crosslink density and increases the sulfur inefficiency.

Investigations in the Field of Rubber Vulcanization. VII. Influence of Organic Accelerators on the Kinetics of Vulcanization and the Properties of Natural-Rubber Vulcanizates

1950 ◽  
Vol 23 (3) ◽  
pp. 563-575
Author(s):  
B. Dogadkin ◽  
B. Karmin ◽  
A. Dobromyslova ◽  
L. Sapozhkova
Keyword(s):  
Activation Energy ◽  
Natural Rubber ◽  
Oxidative Destruction ◽  
Tetramethylthiuram Disulfide ◽  
Vulcanization Kinetics ◽  
Strength Curve ◽  
Increasing Temperature ◽  
Low Sulfur ◽  
Natural Rubber Vulcanizates ◽  
Kinetics Of

Abstract 1. Vulcanization accelerators change all parameters of the kinetic strength curve during the vulcanization of natural-rubber mixtures with low sulfur contents. 2. Calculation of the kinetic constants of the fundamental vulcanization equation proposed by Dogadkin, Karmin, and Gol'berg shows that vulcanization accelerators affect both the kinetics of the interaction of rubber with sulfur and the kinetics of the interaction of rubber with oxygen. 3. Direct experiments on the oxidation of rubber have shown that tetramethylthiuram disulfide and diphenylguanidine retard the process of addition of oxygen to rubber, while mercaptobenzothiazole accelerates this process. 4. Data on the rate of plasticization and change in viscosity of rubber solutions during oxidation indicate that tetramethylthiuram disulfide and diphenylguanidine promote the disintegration of molecular chains of rubber during the oxidative destruction of the latter. 5. The activation energy of the process of oxidation of rubber in the presence of mercaptobenzothiazole corresponds to the activation energy calculated from the fundamental vulcanization reaction for the process of oxidative destruction. This provides additional proof of the participation of oxygen in the vulcanization process. 6. It has been established with the aid of the methyl iodide reaction that accelerators increase the bridge-sulfur content of the vulcanizate, which is present in the form of monosulfides, with one sulfur atom connected to an allyl type radical. 7. With increasing temperature, the tensile strength at the vulcanization optimum increases in mixtures containing tetramethylthiuram disulfide, decreases in mixtures containing mercaptobenzothiazole, and remains unchanged in mixtures containing diphenylguanidine. The limiting strength decreases in all cases with increasing temperature. This phenomenon is explained on the basis of the proposed concepts of the character of vulcanization kinetics and of the nature of the vulcanization optimum.

LUCEFIN GROUP 20NiCrMo2-2(1.6523), 20NiCrMoS2-2 (1.6526)

Alloy Digest ◽  
2020 ◽  
Vol 69 (12) ◽  
Keyword(s):  
Wear Resistance ◽  
Fatigue Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Medium Size ◽  
Case Hardening ◽  
Low Carbon ◽  
High Fatigue

Abstract Lucefin Group 20NiCrMo2-2 and 20NiCrMoS2-2 are low-carbon, Ni-Cr-Mo, alloy case-hardening steels that are used in the carburized or carbonitrided, and subsequently quench hardened and tempered, condition. These steels are, in general, used for medium-size case-hardened parts requiring high fatigue strength and wear resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, and joining. Filing Code: SA-866. Producer or source: Lucefin S.p.A..

SANBAR 20

Alloy Digest ◽  
1999 ◽  
Vol 48 (8) ◽  
Keyword(s):  
Wear Resistance ◽  
Fatigue Strength ◽  
Tensile Properties ◽  
High Strength ◽  
Heat Treating ◽  
Steel Company ◽  
High Fatigue ◽  
Molybdenum Steel ◽  
Rolled Condition

Abstract SANBAR 20 is a high-strength chromium-molybdenum steel with high-fatigue strength and excellent wear resistance in the as-rolled condition. The primary application is use as integral drill rods. This datasheet provides information on composition, hardness, and tensile properties. It also includes information on forming, heat treating, and machining. Filing Code: SA-501. Producer or source: Sandvik Steel Company.

Aging of Natural Rubber Vulcanizates in the Presence of Dithiocarbamates

1959 ◽  
Vol 32 (3) ◽  
pp. 739-747 ◽  
Author(s):  
J. R. Dunn ◽  
J. Scanlan
Keyword(s):  
Stress Relaxation ◽  
Natural Rubber ◽  
Protective Action ◽  
Dicumyl Peroxide ◽  
Vulcanized Rubber ◽  
Aging Properties ◽  
Photochemical Aging ◽  
Natural Rubber Vulcanizates

Abstract The thermal and photochemical aging of extracted dicumyl peroxide-, TMTD (sulfurless)- and santocure-vulcanized rubber, in presence of a number of metal and alkylammonium dithiocarbamates, has been investigated by measurements of stress relaxation. The dithiocarbamates have a considerable protective action upon the degradation of peroxide- and TMTD-vulcanizates, but they accelerate stress decay in santocure-accelerated vulcanizates. The reasons for this behavior are discussed. It is suggested that the excellent aging properties of unextracted TMTD vulcanizates are due to the presence of zinc dimethyldithiocarbamate formed during vulcanization.

Vulcanization kinetics of natural rubber-organoclay nanocomposites

2003 ◽  
Vol 89 (1) ◽  
pp. 1-15 ◽  
Author(s):  
M. A. López-Manchado ◽  
M. Arroyo ◽  
B. Herrero ◽  
J. Biagiotti
Keyword(s):  
Natural Rubber ◽  
Vulcanization Kinetics ◽  
Kinetics Of

Surface Cross-linked UHMWPE: A Low Wear Material with Very High Fatigue Strength

2010 ◽  
Vol 25 (3) ◽  
pp. e72
Author(s):  
Ebru Oral ◽  
Bassem Ghali ◽  
Shannon Rowell ◽  
Brad Micheli ◽  
Orhun Muratoglu
Keyword(s):  
Fatigue Strength ◽  
High Fatigue ◽  
Low Wear ◽  
Very High
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