Swelling of Synthetic Rubbers in Mineral Oils. Effect of Temperature and Aniline Point

1945 ◽  
Vol 18 (2) ◽  
pp. 452-459 ◽  
Author(s):  
P. O. Powers ◽  
B. R. Billmeyer
Keyword(s):  
Tensile Strength ◽  
Effect Of Temperature ◽  
Degree Of Cure ◽  
Volume Increase ◽  
Mineral Oils ◽  
Synthetic Rubber ◽  
Percentage Volume

Abstract The aniline point of hydrocarbon oils and solvents is a satisfactory index of the swelling of oil resistant synthetic rubber compositions. The logarithm of the percentage volume increase varies inversely with the aniline point up to 100 per cent swelling. The slope of the swelling curve is apparently characteristic of each synthetic rubber, and is not affected by loading, temperature or degree of cure. Slight swelling does not greatly decrease the tensile strength, but above 100 per cent swelling the strength is greatly reduced.

Stress Relaxation of Natural and Synthetic Rubber Stocks

1944 ◽  
Vol 17 (3) ◽  
pp. 551-575 ◽  
Author(s):  
A. V. Tobolsky ◽  
I. B. Prettyman ◽  
J. H. Dillon
Keyword(s):  
Tensile Strength ◽  
Free Energy ◽  
Reaction Rate ◽  
Energy Of Activation ◽  
Effect Of Temperature ◽  
Rate Theory ◽  
Air Atmosphere ◽  
Synthetic Rubber ◽  
Commercial Nitrogen ◽  
Natural And Synthetic

Abstract 1. The complete decay of stress in the rubbers studied, held at constant elongation, appeared to involve the rupturing of a definite bond, either at some point along the molecular chain or at the cross-linking bond put in by vulcanization. In the case of a Hevea rubber gum stock the data could be fitted very well by ordinary reaction-rate theory, leading to the conclusion that the free energy of activation required for breaking the bond is 30.4 kcal. per mole of bonds. This result was found to be practically independent of the elongation, and of the presence of carbon black in a Hevea rubber tread stock. This is to be compared to a strength of about 90 kcal. per mole for the C—C bond. 2. In the case of other rubbers (Buna-S, Butaprene-N, Neoprene-GN, and Butyl) the activation free energy for breaking the bond did not vary by more than ±2.0 kcal. per mole from that of Hevea rubber. However, these differences were quite definite. For example, the relaxation of stress in GR-S was slower than in Hevea; a small difference in energy corresponding to a 2:1 ratio in the respective times of decay. 3. The effect of temperature on the relaxation of stress appeared to be of the general type characteristic of chemical reactions. By use of the ordinary formula for expressing rate of reaction in terms of energy of activation, one could predict very closely the behavior of the stress-log time curves at different temperatures. 4. Natural rubber and GR-S vulcanized with paraquinone dioxime and lead dioxide showed relaxation curves very similar to those of the sulfur vulcanized stocks. 5. Relaxation experiments in an ordinary air atmosphere and in an atmosphere of commercial nitrogen showed no appreciable differences. 6. Examination of stretched rubber bands in which the stress had decayed nearly completely (at 100° C) gave no evidences of gross oxidation, such as would make the rubber bands sticky or hard, or of surface deterioration. At higher temperatures, however, the rubber could be observed getting sticky, and then brittle. Specimens in which the stress had completely decayed showed very low tensile strength (by hand test). 7. Antioxidant added to a sulfur-stabilized Buna-S stock caused a definite retardation of the rate of relaxation. 8. Comparison of the results of these experiments with previously recorded observations in the literature indicated that the chemical reaction which ruptured the rubber structure and caused the decay of stress in these experiments (and concomitantly a lowering of tensile strength) was an oxidation of the rubber by small amounts of oxygen, the reaction rate being independent of the oxygen pressure in the range between that present in an ordinary air atmosphere and in a commercial nitrogen atmosphere. 9. The tests suggested a convenient and accurate laboratory method of determining the oxidizability of natural and synthetic rubber stock designed for service.

The effect of temperature and strain rate on the tensile strength of a fast-gas-cooled uranium-2 wt% molybdenum alloy

1985 ◽  
Vol 132 (2) ◽  
pp. 181-191 ◽  
Author(s):  
G.A.C. Boyd ◽  
J. Harding ◽  
P.A. Bleasdale ◽  
K. Dunn ◽  
G.I. Turner
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
Molybdenum Alloy ◽  
Effect Of Temperature

The Synthesis of Isocyanate-Modified Novolak Resins for Use in Natural and Synthetic Rubber

1980 ◽  
Vol 53 (2) ◽  
pp. 239-244 ◽  
Author(s):  
N. D. Ghatge ◽  
B. M. Shinde
Keyword(s):  
Tensile Strength ◽  
Synthetic Rubber ◽  
Natural And Synthetic

Abstract Resin-C and Resin-B give higher values for tensile strength, modulus, and hardness than all other resins.

The Effect of Softeners in Rubber

1953 ◽  
Vol 26 (1) ◽  
pp. 152-155
Author(s):  
Ira Williams
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
High Modulus ◽  
Mineral Oils ◽  
Cohesive Forces ◽  
Commercial Use ◽  
Effect Of Solvents ◽  
Vulcanized Rubber ◽  
Unfavorable Effect ◽  
The Cost

Abstract The use of oils and liquid softeners to assist in the mastication and processing of rubber or to produce softer vulcanized stocks has been standard practice since the early commercial use of rubber. More recently certain synthetic rubbers, polymerized under special conditions, have been treated with rather large amounts of mineral oils, with a resulting decrease in the cost of the rubber and apparently with no unfavorable effect on the rubber in most instances. A number of investigators have reported the effect of swelling agents on the properties of vulcanized rubber. Busse discusses the effect of solvents in a general way. Tiltman and Porritt conclude that the decrease in modulus caused by swelling in benzene is caused by a “loosening of cohesive forces.” Tire treads of natural rubber containing such softeners as pine tar and mineral rubber decrease in wear resistance in proportion to the softener content. Well vulcanized rubber of high modulus is most resistant to swelling in oils. Naunton, Jones, and Smith find that unaccelerated stocks lose the most tensile strength after being swollen, that milling of the raw rubber increases swelling, and that the presence of softeners in the rubber during vulcanization reduces the oil resistance. A limited amount of swelling has been reported to have little effect on the tensile strength of vulcanized natural rubber. Bourbon points out that separating the rubber molecules with solvent decreases the rate of vulcanization.

scholarly journals Utilization of TiO2/gC3N4 nanoadditive to boost oxidative properties of vegetable oil for tribological application

Friction ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 273-287
Author(s):  
Nisha Ranjan ◽  
Rashmi C. Shende ◽  
Muthusamy Kamaraj ◽  
Sundara Ramaprabhu
Keyword(s):  
Vegetable Oil ◽  
Friction And Wear ◽  
Oxidation Behavior ◽  
Tribological Performance ◽  
Effect Of Temperature ◽  
Wear Properties ◽  
Promising Alternative ◽  
Mineral Oils ◽  
Tribological Application ◽  
Friction And Wear Properties

AbstractThe emergence of vegetable oil as a promising alternative lubricant in the tribological application space has fueled research for making these oils as useful as mineral oils. Tribological modification of vegetable oil by the addition of TiO2/gC3N4 nanocomposite (as a nanoadditive) was studied here. The dispersion of the nanoadditive in the vegetable oil showed good oil dispersion stability without the addition of any surfactant. The tribological studies were conducted in a four-ball tester using ASTM standard D5183. In addition, the effect of temperature on tribological performance was also studied to understand the oxidation behavior of vegetable oil. The results showed a significant improvement in friction and wear properties of the optimized nano-oil. The mechanism behind the improvement in friction and wear properties is annotated in this paper.

A Study on the Effect of the Temperature on Mechanical Properties of H90 Copper Strip

2019 ◽  
Vol 950 ◽  
pp. 65-69
Author(s):  
Sun Fei ◽  
Xu Cheng
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Effect Of Temperature ◽  
Basic Material ◽  
Copper Strip ◽  
Study Results ◽  
Different Temperatures ◽  
Strip Test

In order to study the effect of temperature on the mechanical properties of H90 copper strip material, the H90 copper strip test pieces were heated to different temperatures (20~600 °C) for tensile test; the yield strength, tensile strength, elastic modulus and elongation of H90 copper strip at different temperatures were obtained. Based on the test results, the empirical models of yield strength, tensile strength, elastic modulus of H90 copper strip at high temperature were established; the test showed that, with the increase of temperature, the yield strength, tensile strength and elastic modulus of H90 copper strip decreased greatly, and the elongation after fracture first increased-decreased-increased at 20~600 °C. The study results in this paper provide basic material data for analyzing the effect of temperature on the continuous firing of firearms and other weapons.

Elastomer-Resin Blends. Acrylonitrile Type Synthetic Rubber and Polyvinyl Chloride Resins

1949 ◽  
Vol 22 (3) ◽  
pp. 735-755
Author(s):  
D. W. Young ◽  
D. J. Buckley ◽  
R. G. Newberg ◽  
L. B. Turner
Keyword(s):  
Tensile Strength ◽  
Low Temperature ◽  
Polyvinyl Chloride ◽  
Sodium Acetate ◽  
Blocking Temperature ◽  
Acrylonitrile Copolymer ◽  
Rubber Blends ◽  
Synthetic Rubber ◽  
Cure Time ◽  
Acrylonitrile Copolymers

Abstract 1. 1,3-Butadiene-acrylonitrile copolymers were mill-mixed with benzothiazoyl disulfide, sulfur, litharge, and vinyl resins, such as Vinylite (VYNW), and Saran and cured to compounds with good tensile strength, modulus, hardness, solvent resistance, and blocking temperature. 2. Results show that higher acrylonitrile type of copolymers give cured Vinylite-rubber blends with higher tensile strength, higher 100 per cent modulus, and greater ultimate elongation to break than low acrylonitrile copolymers. 3. The low temperature properties of the cured blends improve as the acrylonitrile content of the synthetic rubber is reduced. 4. An effective cure at 287° F is obtained in 15 to 30 minutes by using 2 parts of accelerator and 2 parts of sulfur per hundred parts of 1,3-butadieneacrylonitrile type copolymer-Vinylite blends. Added amounts of sulfur, and accelerator did not improve the properties or decrease the cure time at 287° F. 5. Some of the cured blends studied are free of tackiness at temperatures as high as 230° F. 6. Some stabilizers for vinyls tested as well as sodium acetate can be used to activate sulfur cures in 1,3-butadiene-acrylonitrile copolymer-Vinylite blends to formulate light-colored transparent products.

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