Measurement of the Absorption of Oxygen by Vulcanized Rubber in Air

1939 ◽  
Vol 12 (2) ◽  
pp. 261-268
Author(s):  
A. G. Milligan ◽  
J. E. Shaw
Keyword(s):  
Tensile Strength ◽  
Physical Properties ◽  
Tensile Tests ◽  
Direct Measure ◽  
Mean Values ◽  
Reasonable Time ◽  
Aging Period ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Made In

Abstract It is generally agreed that oxidation is the controlling factor in the decay of rubber compounds. Measurements of the decay of any physical properties—commonly tensile strength—can be made in a convenient time only if the decay is greatly accelerated, and there is always a grave doubt about the equality of the acceleration for different materials. There is also a difficulty in selecting a universally suitable aging period, since the decay of the physical properties is not linear. A direct measure of the rate of oxidation is, in our view, more fundamental and less equivocal. It can, moreover, be made in a reasonable time at a temperature not far removed from service temperatures. Again, whereas tensile tests require several samples of each point in the timecurve to give acceptable mean values, here a single sample suffices for the whole test, and this sample can be simply prepared from a specimen of any form by rasping. The merits and simplicity of the method should commend it to rubber technologists.

Rubber-Lined Equipment. Fundamental Principles of Design

1937 ◽  
Vol 10 (3) ◽  
pp. 564-573 ◽  
Author(s):  
J. R. Hoover ◽  
H. C. Klein
Keyword(s):  
Hydrochloric Acid ◽  
Physical Properties ◽  
Steel Shell ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Wide Range ◽  
Steel Tank ◽  
New Material ◽  
Principles Of Design ◽  
Made In

Abstract IN 1924 a process known as Vulca-lock, discovered by chemists of The B. F. Goodrich Company, made possible the first successful steel tank car for hydrochloric acid service. The tank was lined with acid-resisting vulcanized rubber bonded to the steel shell with adhesion exceeding 500 pounds per square inch. A new material of chemical construction was thus made available in practical form. The resulting widespread and rapidly increasing use of rubber-lined equipment in the processing industries is well known. Basically, the value of such construction lies in properly combining the unique corrosion- and abrasion-resistant properties of rubber with the rigidity, strength, and adaptability of steel or other structural materials. It is essential, therefore, that chemical engineers be familiar with certain principles of design, upon which the successful use of rubber-lined equipment depends. No attempt will be made in this paper to define the broad field of usefulness or the limitations of rubber linings. The fact must be emphasized, however, that an extremely wide range of chemical and physical properties is available in commercial rubber compounds and that these compounds, like metals and alloys, are designed for specific uses.

scholarly journals The Effect of Injection Molding on Physical Properties of EPDM Rubber

2018 ◽  
Vol 210 ◽  
pp. 02039
Author(s):  
Adam Skrobak ◽  
Vojtech Senkerik ◽  
Vaclav Janostik
Keyword(s):  
Tensile Strength ◽  
Injection Molding ◽  
Physical Properties ◽  
Standard Method ◽  
Epdm Rubber ◽  
Tear Strength ◽  
Injection Method ◽  
Rubber Compounds ◽  
Cutting Out ◽  
Injection Molded

The paper a part of research aimed at the alternative of preparing test samples by injection molding. Such an alternative could bring more objective results in the field of testing samples produced in the same technology. The research is aimed at changing the preparation of rubber testing samples - replacing the standard method according to ISO 23529 by the injection method, especially with the use of rubber compounds for injection molding. This article compares and evaluates the selected physical properties (tensile strength and tear strength) of EPDM rubber injection molded samples with samples prepared by the standard method - cutting out of a compression molded plate. The results have shown that using the injection molded samples we will achieve more objective results mainly to determine the tear strength. In the case of tensile strength, the differences are not so significant.

Preliminary Study on Curing of Thick Rubber Article

2015 ◽  
Vol 1134 ◽  
pp. 23-27
Author(s):  
Siti Zulaikha Ibrahim ◽  
Che Mohd Som Said ◽  
Mohamad Asri Ahmad ◽  
Azemi Samsuri
Keyword(s):  
Tensile Strength ◽  
Temperature Region ◽  
The State ◽  
Curing Temperature ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Cure Time ◽  
Zinc Diethyldithiocarbamate ◽  
Preliminary Study ◽  
Rubber Article

In this study, several batches of natural rubber (SMR L) were compounded with three different types of accelerators, which were N-cyclohexylbenzothiazole-2-sulphenamide (CBS), diphenylguanidine (DPG) and zinc diethyldithiocarbamate (ZDEC). ZDEC is known as an ultrafast accelerator. The rubber compounds were cured at 140°C, 130°C, 120°C, 110°C and 100°C in accordance with the temperature gradients observed within the thick rubber block. The main aim of this study is to cure the rubber at each temperature region to the same cure time as that of the outermost region (20 minutes at 140°C). The amount of sulfur and accelerator were adjusted accordingly at each curing temperature to match the state of cure at 140°C. The state of cure of of the vulcanized rubbers were measured using hardness and tensile strength. The same state of cure is achieved if the hardness and tensile strength value are within ±2 IRHD and ±3 MPa, respectively with that of the control vulcanized rubber (hardness and tensile strength cured at 140°C). The results shows that the hardness and tensile strength of the vulcanized rubber at each temperature region are within the expected margins. The results clearly indicated that the type and amount of accelerators, and the amount of sulfur were correctly chosen at each temperature.

The Direct Determination of Oxygen in Rubber. The Adaptation of the Ter Meulen Method to Rubber and Its Application to the Study of Aging

1939 ◽  
Vol 12 (2) ◽  
pp. 269-282 ◽  
Author(s):  
H. I. Cramer ◽  
I. J. Sjothun ◽  
L. E. Oneacre
Keyword(s):  
Tensile Strength ◽  
Physical Properties ◽  
Direct Determination ◽  
Sulfur Poisoning ◽  
Oxidation Products ◽  
Oxygen Bomb ◽  
Vulcanized Rubber ◽  
Relationship Of ◽  
The Relationship

Abstract The ter Meulen method for the direct determination of oxygen has been adapted, with modifications, to the analysis of raw and vulcanized rubbers. Raney nickel has been found to be quite effective as the reducing catalyst and to be satisfactorily resistant to sulfur poisoning. The method has been applied to the study of the aging of vulcanized rubber in the Geer oven and oxygen bomb. From this study the following conclusions may be drawn: (1) The increase in combined oxygen is greater in the oxygen bomb than in the Geer oven. (2) Deterioration of rubber in the oxygen bomb involves oxidation primarily, whereas that occurring in the Geer oven involves not only oxidation but also thermal decomposition followed by volatilization of oxidation products. (3) The effectiveness of an antioxidant in retarding the absorption of oxygen in oxygen-bomb aging agrees well with its ability to maintain the physical properties of the stock in which it is present. (4) The deterioration in physical properties of a rubber stock in the oxygen bomb during the early stages of aging is a linear function of the increase in combined oxygen. For stocks containing antioxidants and diphenylguanidine as the accelerator, an increase in combined oxygen of approximately 1.2% corresponds to a decrease in tensile strength of 50%. (5) The relationship of increase in combined oxygen to decrease in tensile strength seems to be affected not only by antioxidants, but also by accelerators of vulcanization.

Reënforcing Action of Pigment Mixtures on Rubber Compounds

1931 ◽  
Vol 4 (2) ◽  
pp. 248-255
Author(s):  
D. J. Beaver ◽  
J. W. MacKay
Keyword(s):  
Tensile Strength ◽  
Zinc Oxide ◽  
Carbon Black ◽  
Physical Properties ◽  
Chemical Reaction ◽  
Rubber Compounds ◽  
Soft Carbon ◽  
Acidic Compounds

Abstract Mixtures of varying ratios of either channel black or a soft carbon black with whiting, lithopone, or clay show additive physical properties. Mixtures of soft carbon with zinc oxide also show additive properties, while mixtures of channel black and zinc oxide show poorer resistance to abrasion, higher modulus, and higher tensile strength than would be shown by purely additive mixtures. The explanation of these results appears to be found in the chemical reaction between the basic zinc oxide and the acidic compounds in the rubber or on the black. These results have been applied to the formulation of a solid-tire stock which will give a better resistance to abrasion and blow-out when using a soft black than when using a channel black.

A Manometric Test for Oxygen Absorption by Vulcanized Rubber

1942 ◽  
Vol 15 (1) ◽  
pp. 83-90
Author(s):  
Robert H. Johnson
Keyword(s):  
Tensile Strength ◽  
Oxygen Absorption ◽  
Aging Behavior ◽  
Strength Deterioration ◽  
Oxygen Bomb ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Manometric Method ◽  
Set Up ◽  
Bomb Method

Abstract An apparatus can be set up in laboratory glassware that will confirm the results obtained by Dufraisse in his manometric test for oxygen absorption. It has been shown that different rubber compounds possess different tendencies to absorb oxygen. It has also been shown that the differences in the rate at which rubber compounds absorb oxygen are comparable with those differences found in the rate of tensile-strength deterioration of the same compounds aged in the oxygen bomb. This modified Dufraisse manometric method is convenient, efficient, accurate and, above all, a speedy method for measuring the relative aging behavior of vulcanized rubber compounds. Within two hours it is possible to have the results by this method, whereas it is necessary to wait from four days to two weeks for such information by the oxygen bomb method.

High Temperature Vulcanization of Elastomers

1979 ◽  
Vol 52 (4) ◽  
pp. 725-734 ◽  
Author(s):  
A. K. Bhowmick ◽  
R. Mukhopadhyay ◽  
S. K. De
Keyword(s):  
Thermal Conductivity ◽  
Plastic Material ◽  
Plastic Properties ◽  
Microwave Curing ◽  
The Past ◽  
Vulcanized Rubber ◽  
Upper Limit ◽  
Rubber Compounds ◽  
Higher Temperature ◽  
Made In

Abstract Vulcanization is a process which decreases the plastic properties of rubber while maintaining or improving the elastic properties. The term vulcanization has been applied in the past mainly to the reaction of rubber with sulfur, but now is generally used for the process which results in changes in properties, by sulfur or some other agent. There are four principal changes brought about by vulcanization: (1) rubber is changed from essentially a plastic to a non-plastic material; (2) rubber is changed from a material soluble in a number of solvents to one which is insoluble; (3) rubber is changed to a material with greatly improved physical properties; (4) these properties of vulcanized rubber are maintained over a much wider range of temperature than those of unvulcanized rubber. What is meant by high vulcanizing temperature? There is no unique answer. About 160°C can be taken conveniently as the lower limit; this temperature has been suggested as the highest suitable for some normally compounded sulfur curing rubbers. The upper limit may be 220°C, above which the polymer may begin to degrade. The range in practice extends up to about 250°C in fluid beds and salt baths. Practical vulcanization processes apply heat to the outside of the article being cured and rely on the conduction of heat to the inside. Since no drastic change can be made in the thermal conductivity of practical rubber compounds by compounding modifications, higher temperature is a common method of achieving faster vulcanization. Higher curing temperatures are used in the newer curing or molding processes such as injection molding, the liquid curing medium (LCM) process, and microwave curing.

Temporary-Creep and Post-Creep Properties of Aquaculture Netting Materials With UHMWPE Fibres

2013 ◽  
Author(s):  
Heidi Moe Føre ◽  
Per Christian Endresen ◽  
Østen Jensen
Keyword(s):  
Tensile Strength ◽  
Room Temperature ◽  
Breaking Strength ◽  
Tensile Tests ◽  
Test Results ◽  
Load History ◽  
Elongation At Break ◽  
Creep Properties ◽  
Mean Values ◽  
Creep Strains

This paper presents test results on temporary-creep properties, recovery of strain post creep and post-creep tensile properties of a Raschel knitted netting material with a combination of UHMWPE and Polyester fibres. Specimens of the material were subjected to uniaxial loading over a period of 30 minutes, at a constant creep target load of 10–90 % of average tensile strength. The specimens were wet and tested in room temperature. The netting structure experienced significant creep strain, with mean values in the range of 1.3–4.5 %, increasing with increased creep target load. Large proportions of the elongation accumulated during on-loading and creep were long lasting and possibly permanent. Tensile tests showed that for the highest creep target load, strength and elongation at break increased by 17 %. The UHMWPE-netting experienced larger creep strains than PA6-netting for relatively large creep target loads (60–90 % of the average breaking strength), while creep strains were smaller for low loads. PA6-netting had a larger and faster recovery of strain post creep than the UHMWPE-netting, and the length and force at break were not significantly affected by the creep load history.

Effect of Stearic Acid on Reclaimed Rubber

1929 ◽  
Vol 2 (4) ◽  
pp. 627-632
Author(s):  
H. A. Winkelmann ◽  
E. B. Busenburg
Keyword(s):  
Tensile Strength ◽  
Stearic Acid ◽  
Physical Properties ◽  
Vulcanized Rubber

Abstract 1—Stearic acid does not compare with other softeners in plasticizing efficiency when used in contact with vulcanized rubber scrap during devulcanization. 2—Stearic acid when added as a softener to devulcanized scrap on the mill prior to refining imparts properties which are very desirable. (a) Makes the reclaim batch more plastic, (b) improves tubing and calendering properties, (c) reduces nerve without production of excess tack, (d) improves curing properties (higher tensile strength, higher modulus, and improved molding properties) of reclaimed rubber, (e) when pigments are added it gives better dispersion with improved physical properties. 3—Stearic acid when used in compounds containing reclaimed rubber improves the curing properties of these compounds.

Aging of Rubber in the Oxygen Bomb at Room Temperature

1943 ◽  
Vol 16 (4) ◽  
pp. 924-925
Author(s):  
J. R. Scott
Keyword(s):  
Tensile Strength ◽  
Oxygen Concentration ◽  
Room Temperature ◽  
Accelerated Aging ◽  
Natural Aging ◽  
Tensile Tests ◽  
Oxygen Bomb ◽  
Vulcanized Rubber ◽  
Accelerated Aging Test ◽  
Aging Test

Abstract The work described below was carried out as a first step in determining whether an oxygen-bomb test at room temperature could be used as an accelerated aging test for unvulcanized rubber compositions, e.g., as used on surgical and adhesive plasters and for combining shoe fabrics, because a high-temperature test is unsatisfactory in such cases, owing to the melting of the compositions. The only infallible way of assessing the value of an accelerated test for such compositions is by comparison with natural aging, but as this is a very lengthy process and as the deterioration is difficult to measure quantitatively, it was decided to make preliminary tests on the effect of high oxygen concentration at room temperature by using vulcanized rubber. Although the results proved to be negative so far as the original purpose of the work was concerned, it is considered of interest to place them on record in view of the prominence given in some papers on aging to the relationship between oxygen concentration and rate of oxidation and deterioration of rubber. A mix composed of rubber 100, sulfur 3, zinc oxide 5, stearic acid 1, and diphenylguanidine 0.75, was vulcanized for 30 minutes at 153° C. Tensile tests, using standard ring-specimens and the Schopper machine, were made on unaged specimens and on specimens that had been aged (1) in an oxygen bomb at 300 lb. per sq. in. oxygen pressure and at room temperature (about 10° C), (2) in a Geer oven at 70° C. Four rings were used for each test, the tensile strength and breaking elongation figures quoted being the average for the two rings giving the highest tensile strength, and the figures for the elongations at constant loads the average of all four rings.

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