Hysteretic and Elastic Properties of Rubberlike Materials under Dynamic Shear Stresses

1944 ◽  
Vol 17 (3) ◽  
pp. 597-616 ◽  
Author(s):  
J. H. Dillon ◽  
I. B. Prettyman ◽  
G. L. Hall
Keyword(s):  
Natural Rubber ◽  
Elastic Properties ◽  
Shear Stresses ◽  
Dynamic Shear ◽  
Small Problem ◽  
Principal Problem ◽  
Synthetic Rubber ◽  
Truck Tire ◽  
Hysteretic Properties ◽  
Rubberlike Materials

Abstract The principal problem of the rubber technologist and engineer today is that of applying the various types of synthetic rubber to products which undergo rapid repeated flexure. All commercially available synthetic rubbers possess a greater hysteresis defect than does natural rubber. Hence, the task of designing a product such as a large truck tire, where heat development has been no small problem even with natural rubber, is much more difficult. Consequently, the accompanying problem of evaluating the hysteretic properties of rubberlike materials has assumed new importance.

Hysteretic and Elastic Properties of Rubberlike Materials Under Dynamic Shear Stresses

1944 ◽  
Vol 15 (4) ◽  
pp. 309-323 ◽  
Author(s):  
J. H. Dillon ◽  
I. B. Prettyman ◽  
G. L. Hall
Keyword(s):  
Elastic Properties ◽  
Shear Stresses ◽  
Dynamic Shear ◽  
Rubberlike Materials

The Weber Color Test for the Identification of Natural Rubber

1945 ◽  
Vol 18 (4) ◽  
pp. 902-904 ◽  
Author(s):  
I. F. C. Parker ◽  
W. C. Wake
Keyword(s):  
Organic Chemistry ◽  
Positive Result ◽  
Natural Rubber ◽  
Natural Product ◽  
Color Test ◽  
Gutta Percha ◽  
Synthetic Rubber ◽  
Violet Color ◽  
Color Reactions ◽  
Rubberlike Materials

Abstract The Weber color reaction, mentioned in a recent note, has become of importance in detecting natural rubber in mixtures in which it may be considerably diluted with synthetic rubber or nonrubber materials. The detailed instructions for carrying out the test are given elsewhere, and Stern has published a table which shows also the colors obtained when the test is applied to rubbers other than the natural product. It is clear from this table, and is confirmed by our experience, that the strong violet color developed is distinctive for natural rubber and gutta-percha, provided that the material has been extracted with acetone. However, color reactions in organic chemistry are rarely found to be as specific as earlier workers have claimed, and work is being carried out in these laboratories to establish the limitations of the reaction when applied to rubberlike materials. With very few exceptions, synthetic rubbers and rubberlike materials available at present do not give a positive result with this test, although very faint violet colors, which cannot be confused with a positive result, are sometimes obtained. Those giving any violet color are listed in Table I.

Synthetic Rubber

1934 ◽  
Vol 7 (1) ◽  
pp. 40-88
Author(s):  
G. S. Whitby ◽  
M. Katz
Keyword(s):  
Natural Rubber ◽  
Tensile Properties ◽  
Elastic Properties ◽  
Raw Materials ◽  
Early Period ◽  
Synthetic Rubber ◽  
Active Subject ◽  
Chloroprene Rubber ◽  
Post War

Abstract In the early period isoprene was recognized as the mother substance of caoutchouc, and its ability to undergo polymerization to a rubber-like product was demonstrated. During the pre-war period serious efforts were begun to devise processes for the synthesis of rubber which would be commercially feasible. Attention was concentrated on the preparation of the necessary monomeric dienes from cheap raw materials available in substantially unlimited quantity. The rubber-like polymers prepared were markedly inferior to natural rubber. During the war the actual manufacture of synthetic rubber from dimethylbutadiene and its utilization in the production of certain lines of rubber goods was, owing to the exigencies of the time, undertaken in Germany. After a lull, synthetic rubber in 1925 again became an active subject for research. In so far as butadiene and its homologs are concerned, attention during this post-war period has been concentrated on methods of polymerizing the dienes rather than on methods of preparing them, and marked progress has been made. Recently a novel form of synthetic rubber has been prepared by polymerizing 2-chlorobutadiene. Chloroprene rubber resembles vulcanized natural rubber in elastic properties more closely than any previous synthetic rubber preparation and, moreover, has advantages over natural rubber in certain respects. Experiments on the swelling of chloroprene rubber and its tensile properties are reported.

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.

Effect of Dynamic Shear Force on Fastener Loosening in Assemblies

1997 ◽  
Author(s):  
Yubo Dong ◽  
Daniel P. Hess
Keyword(s):  
Cantilever Beam ◽  
Static Load ◽  
Nodal Line ◽  
Shear Stresses ◽  
Dynamic Shear ◽  
Bernoulli Beam ◽  
Cyclic Shear ◽  
Nodal Lines ◽  
Inertial Loading ◽  
Euler Bernoulli Beam

Abstract Placement and orientation of fasteners in assemblies is generally based on convenience or static load and strength considerations. Vibration and other dynamic loads can result in loosening of threaded product, particularly when cyclic shear stresses are present. This paper investigates the placement of a bolt and nut on a compound cantilever beam subjected to dynamic inertial loading. Calculations for an inertial loaded, cantilever, Euler-Bernoulli beam show that the dynamic shear stress is maximum near the dynamic nodal lines, and essentially vanishes near the anti-nodes. Experiments with a compound cantilever beam assembly with one fastener reveal that loosening occurs more readily when the bolt and nut are placed near a nodal line. Data presented include time to loosen, break-away torque, and acceleration level. The data shows that fastener integrity is maintained for longer periods of time and with lower tightening torques, when the bolt and nut are positioned away from nodal lines where shear stresses are lower, even though acceleration levels are higher.

Chlorinated Isoprene Rubbers in Adhesive Composites

2017 ◽  
Vol 44 (5) ◽  
pp. 25-28 ◽  
Author(s):  
A.A. Zuev ◽  
L.R. Lyusova ◽  
N.P. Boreiko
Keyword(s):  
Natural Rubber ◽  
Scientific Research ◽  
Scientific Research Institute ◽  
Physicomechanical Properties ◽  
Butadiene Rubber ◽  
Technological Factors ◽  
Nitrile Butadiene Rubber ◽  
Synthetic Rubber ◽  
Adhesive Materials ◽  
Isoprene Rubber

Now there is not a single area of industry that can do without adhesive elastomer materials. Composites based on synthetic rubbers comprise 75% of the total volume of adhesive materials produced, which is due to the combination of unique properties typical of the elastomer base of the adhesive. The base of many imported adhesives for the bonding of rubber to metal is chlorinated natural rubber. As an alternative, chlorinated synthetic isoprene rubber has been proposed, developed at the Scientific Research Institute for Synthetic Rubber in St Petersburg. The chlorinated isoprene rubber was compared with imported chlorinated natural rubber in adhesive composites, and the physicomechanical properties of mixes based on a blend of chlorinated rubber and nitrile butadiene rubber were investigated. The investigation was conducted on chlorinated natural rubber of grade Pergut S20, chlorinated isoprene rubber SKI-3, and nitrile butadiene rubbers of grades BNKS-28AMN and SKN-26S. The influence of the ratio of chlorinated rubber to nitrile butadiene rubber and the technological factors of mix preparation on the properties of films produced from them was established. It was shown that, in terms of the level of properties, home-produced chlorinated rubber can be used as the base for adhesives for hot bonding of rubber to metal instead of imported Pergut S20.

scholarly journals Sustainability and Competitiveness of Thailand’s Natural Rubber Industry in Times of Global Economic Flux

2017 ◽  
Vol 14 (1) ◽  
pp. 169
Author(s):  
Palapan Kampan
Keyword(s):  
Natural Rubber ◽  
Positive Relationship ◽  
New Technologies ◽  
Pearson Correlation ◽  
The United States ◽  
Bivariate Correlation ◽  
Synthetic Rubber ◽  
Reinforcing Factors ◽  
Strong Positive Relationship ◽  
Correlation Tests

This study assesses economic, legal, and environmental conditions that Thai rubber farmers face, and evaluates actions they can take to increase incomes. Statistical analyses determine relationships between prices of oil, natural and synthetic rubber. Pearson correlation tests found a strong positive relationship (r = 0.887) between the price of Brent crude and Thai ribbed smoked sheets, and a moderate positive relationship between price changes in Brent and synthetic rubber (r = 0.648). Regression analysis showed Brent oil price is a good predictor of natural rubber prices. Moderate to strong positive relationships were also found between natural rubber price and gross domestic product of Japan, China, and the United States. Criminal antitrust behavior in rubber industries appeared to interfere with normal pricing in rubber markets. No significant bivariate correlation was found between rainfall in Thailand and natural rubber price, production, or export although flooding and other environmental issues clearly affected rubber farms. A survey of options showed Thai rubber farmers can improve livelihoods best through collective purchase and use of new technologies, and by integrating into downstream supply chain industries. At very least, farmers are urged to abandon monocrop methods and supplement incomes with fruit, fish, livestock, or pigs. stment budget, 2) architectural Aesthetic, and 3) utilization. Additionally, background of the interviewees is one of reinforcing factors for decision on universal design investment.

Determination of Peroxides in Synthetic Rubbers

1945 ◽  
Vol 18 (4) ◽  
pp. 874-876
Author(s):  
Richard F. Robey ◽  
Herbert K. Wiese
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Quantitative Determination ◽  
High Molecular Weight ◽  
Active Oxygen ◽  
Lower Molecular Weight ◽  
Synthetic Rubber ◽  
High Molecular Weight Polymers ◽  
Methanol Solutions

Abstract Peroxides are found in synthetic rubbers either as the result of attack by oxygen, usually from the air, or as a residue from polymerization operations employing peroxide catalysts. Because of possible detrimental effects of active oxygen on the properties of the rubber, a method of quantitative determination is needed. The concentration of peroxides in substances of lower molecular weight may be determined with ferrous thiocyanate reagent, either titrimetrically as recommended by Yule and Wilson or colorimetrically as by Young, Vogt, and Nieuwland. Unfortunately, many highly polymeric substances are not soluble in the acetone and methanol solutions employed in these procedures. This is also the case with hydrocarbon monomers, such as butadiene, containing appreciable concentrations of soluble high molecular weight polymers. Bolland, Sundralingam, Sutton and Tristram recommended benzene as a solvent for natural rubber samples and the reagent made up in methanol. However, most synthetic rubbers are not readily soluble even in this combination. The following procedure employs the ferrous thiocyanate reagent in combination with a solvent capable of maintaining considerable concentrations of synthetic rubber in solution. The solvent comprises essentially 20 per cent ethanol in chloroform.

S. K.—The Russian Synthetic Rubber from Alcohol. A Survey of the Chemistry and Technology of the Lebedev Process for Producing Sodium-Butadiene Polymers

1942 ◽  
Vol 15 (3) ◽  
pp. 403-429 ◽  
Author(s):  
Anselm Talalay ◽  
Leon Talalay
Keyword(s):  
Natural Rubber ◽  
Petroleum Products ◽  
Economic Independence ◽  
Russian Government ◽  
Experimental Station ◽  
Synthetic Product ◽  
Synthetic Rubber ◽  
Economic Council ◽  
Factory Layout ◽  
Continue Work

Abstract The question of producing synthetic rubber industrially was raised in Russia as early as 1918, and was fostered principally by the quest of the U.S.S.R. for economic independence. Having recognized that 1,3-butadiene is one of the simplest organic compounds capable of being polymerized to a rubberlike substance, the Russian Government provided funds for research in two directions: (1) To investigate the possibility of obtaining butadiene from a mixture of ethyl alcohol and acetaldehyde, according to the method suggested by Ostromislensky in 1915, for which purpose a pilot plant was erected in Moscow at the Bogatyr Rubber Company. (2) To continue work started in 1915 by B. V. Buizov in the laboratory of the Leningrad Treugolnik Rubber Plant, using petroleum products as a source of butadiene. By 1922 the Moscow plant had proved that Ostromislensky's process had no industrial future, for it yielded only 5 to 6 per cent of butadiene instead of the 15 to 18 per cent originally expected. The experimental station operated by Buizov had likewise met with little success by 1925. Early in 1926, therefore, the Superior Economic Council of the U.S.S.R. announced an open competition for the best industrial method of producing synthetic rubber, setting January 1, 1928 as the deadline. The qualifying conditions were rather exacting. They specified that the synthetic rubber should be neither inferior in quality to, nor substantially different in price from, natural rubber. Aside from a detailed description of the process and a two-kilogram sample of the synthetic product, the competition called for plans of a complete factory layout for its manufacture.

Vibration Properties of Rubberlike Materials Dependence on Temperature

1943 ◽  
Vol 16 (2) ◽  
pp. 400-416 ◽  
Author(s):  
R. B. Stambaugh
Keyword(s):  
Internal Friction ◽  
Natural Rubber ◽  
Critical Temperatures ◽  
Cohesive Forces ◽  
Exponential Law ◽  
Vibration Properties ◽  
Inverse Effect ◽  
Similar Materials ◽  
Straight Lines ◽  
Rubberlike Materials

Abstract 1. The vibration modulus and resilience are independent of the frequency of vibration if the temperature is constant. 2. The internal friction is approximately inversely proportional to the frequency. 3. The modulus decreases as temperature increases. Curves for synthetic stocks at high temperatures are not very different from those of rubber at low temperatures. 4. Resilience rises linearly with temperature. Rubber shows a transition from one slope to another at about 25° C. 5. The dependence of the internal friction of rubber and similar materials on temperature follows the same exponential law as the viscosity of liquids. At certain critical temperatures sudden changes occur in the cohesive forces, which cause a transition from one curve to another. For the natural rubber sample this occurs at about 17° C. 6. The amplitude of vibration has a large inverse effect on the modulus and friction, which cannot be explained by the temperature rise of the sample due to heat generated in it. The effect may be due to nonlinearity of the stress-strain curves. 7. Modulus and friction are affected by temperature in the same way, indicating the dependence of both on some fundamental characteristic of the molecular structure. Natural rubber requires two straight lines for representation on the modulus-friction plot, the junction occurring at about 25° C.

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