Physical Testing of Synthetic-Rubber Products

1944 ◽  
Vol 17 (4) ◽  
pp. 974-983
Author(s):  
L. V. Cooper
Keyword(s):  
Natural Rubber ◽  
Raw Materials ◽  
Large Field ◽  
Design Engineers ◽  
Automobile Design ◽  
Synthetic Rubber ◽  
Rubber Compounds ◽  
Short Period ◽  
Physical Testing ◽  
High Degree

Abstract Evaluation that will predict with a high degree of accuracy the suitability for service of any product is the object of all physical testing. Over a comparatively short period of about twenty-five years, rubber technologists have evolved a series of tests which have evaluated natural rubber compounds reasonably well. When it became necessary to evaluate rubber substitutes, it was only natural that the same tests would be applied. The results obtained convinced everyone that these materials were definitely not equivalent substitutes, and to use them involved more than just replacement. Although the background is not so extensive as might be desired, the A.S.T.M. Committee D-11 on Rubber Products has learned enough about these materials to be able to present certain facts and recommendations to industry in general with regard to specifications covering synthetic rubbers and products made from them. The entire field of physical testing is quite extensive, as it covers not only finished products but the component raw materials from the time they are received until they emerge as final products ready to be put into service. Also, in this large field, not everyone is interested in the same phase of testing synthetic rubber products. Tire development engineers are not interested in load deflection figures, which are so essential to automobile design engineers, and the latter have no concern with adhesion to fabric which must be considered by the pneumatic tire technologists and those concerned with hose and belting. This paper is intended to deal primarily with some of the physical properties which affect the service of finished products.

Liquid guayule natural rubber, a renewable and crosslinkable processing aid in natural and synthetic rubber compounds

2020 ◽  
Vol 276 ◽  
pp. 122933
Author(s):  
Xianjie Ren ◽  
Cindy S. Barrera ◽  
Janice L. Tardiff ◽  
Andres Gil ◽  
Katrina Cornish
Keyword(s):  
Natural Rubber ◽  
Synthetic Rubber ◽  
Rubber Compounds ◽  
Natural And Synthetic

Stress Relaxation in Compression of Rubber and Synthetic Rubber Vulcanizates Immersed in Oil

1953 ◽  
Vol 26 (2) ◽  
pp. 336-349
Author(s):  
J. R. Beatty ◽  
A. E. Juve
Keyword(s):  
Stress Relaxation ◽  
Natural Rubber ◽  
Synthetic Rubber ◽  
Rubber Compounds ◽  
Frictional Forces ◽  
Practical Implications

Abstract The practical implications of this study are that rubber compounds which swell in the presence of oil have a property which may be utilized in some applications where it may serve a useful purpose. Examples are O-ring seals and other types of gaskets, where the rubber is used in compression. In these cases the stress decays more slowly with time, and in some cases the force would increase, and the tendency to leakage would be minimized. In these experiments the sample was relatively unconfined except for the direction of loading with only low frictional forces which tended to prevent increase in volume. It was noted (Figures 4 and 6) that, with natural rubber and GR-S at 70° C the stress reached a maximum between 1000 and 10,000 hours, which is a result of the sample reaching equilibrium with respect to swelling by the oil, and the stress then decreases, depending on the oxidative scission of bonds in the same manner as found for tests conducted in air. However, according to Scott, the attack of swelling agents accelerates oxidation; so it is possible that this oxidative scission might be in addition to that normally measured in air.

Vistanex Polybutene—Rubber Blends

1941 ◽  
Vol 14 (2) ◽  
pp. 386-397 ◽  
Author(s):  
S. Longman
Keyword(s):  
Natural Rubber ◽  
Raw Materials ◽  
Petroleum Products ◽  
The Other ◽  
Partial Substitution ◽  
Manufacturing Equipment ◽  
Rubber Industry ◽  
Rubber Blends ◽  
Synthetic Rubber

Abstract From the foregoing data on blends of Vistanex Polybutene and rubber, it is evident that these two materials complement one another. Each has properties which the other lacks, and blends of the two can be made to emphasize the more desirable properties of either one. Extreme flexibility in compounding these blends is possible, since they are perfectly compatible in milled compounds. Therefore, great latitude is given in compounding of these blends to secure any range or degree of properties possible with either of the components. Vistanex Polybutenes should not be considered as synthetic rubber, because they will not vulcanize, and they lack certain characteristics of vulcanized natural rubber. More properly Vistanex Polybutenes should be considered as modifying agents for partial substitution of natural rubber. In many cases, this substitution of a part of the natural rubber in a compound by Vistanex Polybutene confers definite advantages and improves qualities of such compounds for special uses. Therefore, Polybutenes, even in normal times, have a very definite field of usefulness and, in the event that imports of natural rubber become restricted, the availability of the Vistanex Polybutenes in quantity will be of increasing importance to the rubber industry. Since the raw materials for the manufacture of Vistanex Polybutene are petroleum products, the availability of raw materials is a source of no difficulty in this country. Likewise, the manufacturing equipment is not excessively expensive, and, with expanded production, lowered prices may confidently be expected.

Lignin as a Compounding Ingredient for Natural Rubber

1957 ◽  
Vol 30 (2) ◽  
pp. 639-651 ◽  
Author(s):  
I. Sagajllo
Keyword(s):  
Natural Rubber ◽  
High Resistance ◽  
Pilot Plant ◽  
Test Results ◽  
Dry Powder ◽  
Synthetic Rubber ◽  
Rubber Compounds ◽  
Pilot Plant Scale ◽  
Made In ◽  
Natural And Synthetic

Abstract Important claims have been made in recent years regarding the capacity of lignin to reinforce natural and synthetic rubber. In 1949 Dawson reviewed the literature on the use of lignin in rubber and drew particular attention to the work of Keilen and Pollak who had shown that in certain circumstances lignin could be considered to rival EPC black in its ability to yield strong GR-S vulcanizates with high resistance to tear. Raff and his coworkers subsequently showed that the reinforcement of GR-S by lignin is enhanced if the lignin, before coprecipitation with the latex, is subjected to oxidation; other workers studied the application of lignin to the reinforcement of different elastomers, the influence of coprecipitation conditions on the properties of the product, and the problem of overcoming the delaying effect of lignin on vulcanization of lignin-natural rubber coprecipitates. Keilen and Pollak in their experiments incorporated lignin into rubber by coprecipitation at the latex stage, but they indicated that similar results could be obtained if lignin “in the gelled state” was added to rubber by milling. No reinforcement was observed however when lignin was added to rubber as a dry powder. Lignin is potentially an abundant and cheap material which according to the above claims should extend the range of useful compounds available to rubber manufacturers. The present paper describes work undertaken to gain firsthand knowledge of the technique of coprecipitating lignin with natural rubber from preserved latex, to learn something about the properties of natural rubber compounds prepared from lignin coprecipitates, and to study possible ways of incorporating lignin into rubber by means other than coprecipitation. It also records test results for masterbatches prepared by the Rubber Research Institute of Malaya from fresh latex on a pilot plant scale.

The Analysis and Forecast about the Supply and Demand of China's Rubber Raw Materials Based on Grey Model

2013 ◽  
Vol 404 ◽  
pp. 796-801
Author(s):  
Zhao Jun Wang ◽  
Zhou Lin ◽  
Shuai Liu
Keyword(s):  
Natural Rubber ◽  
National Economy ◽  
Raw Materials ◽  
Supply And Demand ◽  
Grey Model ◽  
Forecasting Model ◽  
Rubber Industry ◽  
Grey Forecasting ◽  
Synthetic Rubber ◽  
The Status

The rubber industry is an important sector in the national economy. The article took the natural rubber and synthetic rubber as the main studying objects to analyze and forecast the amount of supply and demand of Chinas rubber raw materials. Analyzed the status of supply and demand of Chinas rubber raw materials from 2006 to 2011, and established the Grey Forecasting Model to forecast the supply and demand from 2012 to 2017 in China, and concluded that the prosperous supply and demand of rubber raw materials would be continued in the future.

Effect of Ingredient Loading on Vulcanization Characteristics of a Natural Rubber Compound

2015 ◽  
Vol 1125 ◽  
pp. 50-54 ◽  
Author(s):  
Bryan B. Pajarito
Keyword(s):  
Natural Rubber ◽  
Raw Materials ◽  
Fractional Factorial ◽  
High Loading ◽  
Rubber Compound ◽  
Cure Rate ◽  
Used Oil ◽  
Rubber Compounds ◽  
Cure Time ◽  
Viscous Torque

Rheometric properties of rubber compounds are usually monitored with time during the course of vulcanization at constant temperature. The measured vulcanization characteristics of rubber compound are used for quality control and evaluation of raw materials and product formulations. With the high number of ingredients used in typical formulations, it is important to identify ingredients which significantly affect the vulcanization characteristics of a rubber compound. This study reports the vulcanization characteristics of a natural rubber compound at 60 °C as function of ingredient loading. Rubber sheets are compounded according to a 212-8 fractional factorial design of experiment, where ingredients are treated as factors varied at low and high loadings. Vulcanization curves, which are time plots of elastic torque S’, viscous torque S”, and tan δ = S”/S’, are measured for each rubber sheet using a moving die rheometer. The following responses are then determined from the vulcanization curves for data analysis: minimum elastic torque ML, maximum elastic torque MH, torque difference ∆S = MH – ML, scorch time ts1, cure time t’90, cure rate index CRI = 100/ (t’90 – ts1), S” and tan δ values at ML and MH. Analysis of variance (ANOVA) shows used oil to be the main ingredient affecting vulcanization of the natural rubber compound (ML, MH, ∆S, ts1, S” at ML and MH), followed by sulfur (MH, ∆S, CRI), calcium carbonate CaCO3 (S” at ML, tan δ at MH) and diphenylguanidine DPG (ts1). High loading of used oil lowers the elastic and viscous response of the rubber compound, while increases the time for scorch. Increased loading of sulfur significantly enhances the elastic torque and cure rate of the compound. High loading of CaCO3 improves the viscous response, while DPG significantly shortens the scorch time of the rubber compound.

The Tear Resistance of Rubber Compounds

1941 ◽  
Vol 14 (4) ◽  
pp. 863-876
Author(s):  
G. A. Patrikeev ◽  
A. I. Melnikov
Keyword(s):  
Natural Rubber ◽  
Improved Method ◽  
Synthetic Rubber ◽  
Rubber Compounds ◽  
Tear Resistance ◽  
Natural And Synthetic

Abstract 1. An improved method of measuring tear resistance was developed. The samples which were examined were cut in the direction of stretching. 2. The relation between tear resistance and time of vulcanization was investigated. 3. The tear resistances of synthetic and natural rubbers were compared. 4. It is shown that the tear resistance of samples of natural and synthetic rubber depends on the depth of the initial cut. With short cuts, natural rubber has a higher tear resistance than synthetic rubber, but this difference decreases as the cut is made longer. 5. It is established that the tear resistance of thin rubber specimens is smaller than that of thicker specimens. 6. The mechanism of tear resistance is discussed. Factors such as deformation are considered.

The Fibrous Properties and Abrasion Resistance of Synthetic Rubber Compounds

1941 ◽  
Vol 14 (4) ◽  
pp. 786-798
Author(s):  
A. Kusov
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Abrasion Resistance ◽  
Depth Of Cut ◽  
Fiber Direction ◽  
Oxide Content ◽  
Synthetic Compounds ◽  
Synthetic Rubber ◽  
Rubber Compounds ◽  
Tear Resistance

Abstract 1. A method of measuring the tear resistance of rubber compounds was developed. This method has a number of advantages over other methods (Goodrich, Heidensohn, Goodyear, etc.), including the following. (a) The symmetrical shape and the large surface of tearing (20 sq. cm.). This excludes the possibility of short, accidental tears, and enables better observation of the nature of the tear. (b) Owing to the small size of the clamped portion of the specimen compared to the size of the tearing surface, “end effects” are largely eliminated. (c) Tearing forces are registered periodically (every 10 seconds), and it is possible in this way to determine the total energy expended on tearing, and the nature of its changes. (d) The experiments are easy to perform, and the apparatus is simple. 2. The addition of carbon black (10–100 per cent) to synthetic rubber compounds increases considerably the tear resistances of the vulcanized products. The best results are obtained with compounds containing between 50 and 75 per cent of carbon black. 3. A zinc oxide content of between 8 and 14 per cent improves the tear resistances of compounds of both synthetic and natural rubbers. 4. Compounds with increased fibrous structure show increased abrasion resistance when the fiber direction is parallel to the movement of the abrading surface. 5. Compounds cured for short times only show low tear resistances when made of synthetic rubbers of both low (0.31) and high (0.87) plasticity. The best results are obtained with compounds made of synthetic rubber of medium plasticity (0.53 and 0.40) (see Figure 4). 6. When comparing tear resistances, it is of the utmost importance to maintain the thickness of test-specimens within narrow limits. It is desirable to keep variations within 10–15 per cent. 7. The weakening of the uncut portion of a test-specimen with increase in depth of cut is less pronounced with compounds of synthetic rubber than it is with natural rubber compounds, particularly in the case of overcured samples. With synthetic compounds, this weakening effect varies 2–3 times; with natural rubber compounds it is 3.5–6.5 times. The relation between tear resistance and depth of cut is shown in Figure 5 and Table VI. 8. Carbon black compounds of both synthetic and natural rubbers exhibit various structural forms of tearing. Synthetic rubber compounds with low tear resistances show simple and smooth tearing surfaces, usually in the prolongation of the cut, or at a slight angle to it (Figure 1, type A or intermediate between A and B). Synthetic compounds with high tear resistances show complicated tearing surfaces (Figures 6 and 7, types C, D, E and F).

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.

A Method of Testing the Elasticity of Synthetic Rubbers at Low Temperatures

1943 ◽  
Vol 16 (4) ◽  
pp. 888-896
Author(s):  
George D. Kish
Keyword(s):  
Natural Rubber ◽  
Low Temperatures ◽  
New Product ◽  
Elastic Behavior ◽  
Accurate Data ◽  
Synthetic Rubber ◽  
Rubber Compounds

Abstract With the appearance of many new synthetic rubber compounds, the need has arisen for quick and practical testing to determine their comparative applicability to uses formerly filled by natural rubber compounds. One of the most important points is the elastic behavior of synthetic rubbers at low temperatures, and such information is imperative when synthetics are to be introduced into the design of a new product. To obtain accurate data, an instrument termed an Elastensometer was devised.

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