Reënforcing Action of Pigment Mixtures on Rubber Compounds

1931 ◽  
Vol 4 (2) ◽  
pp. 248-255
Author(s):  
D. J. Beaver ◽  
J. W. MacKay

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.

1953 ◽  
Vol 26 (1) ◽  
pp. 156-165
Author(s):  
Ira Williams

Abstract The presence of pigments in rubber compounds produces physical properties which are of importance both before and after vulcanization. The ability of the unvulcanized mixture to calender or extrude smoothly with minimum swelling and to maintain shape during air cures, and the tensile strength, tear resistence, and abrasion resistance of vulcanized stocks all are affected. The methods by which these changes are brought about have been considered by many investigators and have been summarized by Parkinson1 and by Shepard, Street, and Park. Since carbon black is the most generally useful reinforcing pigment, it is natural that investigations have been directed particularly to this product. However, while it is recognized that differences exist in the final properties imparted by different pigments, all solid compounding ingredients have something in common. This point can be illustrated by the tear resistance imparted by such a variety of pigments as carbon black, zinc oxide, whiting, and clay. The effect of volume loading on the tear resistance of vulcanized stocks containing these materials, determined by the method of Zimmerman is shown in Figure 1. The effect of solid compounding ingredients can be studied only by considering the compound as a whole, since the properties are determined very largely by the relation between the solid particle and the matrix which surrounds it. Since the introduction of the many types of synthetic rubbers, the complexity of the problem has been greatly increased by the different states of polymerization, which affect the ability of the rubber to conform to the shape of the pigment particle and by the differences in polar nature which affect the type and the degree of adhesion between filler and matrix.


1940 ◽  
Vol 13 (4) ◽  
pp. 918-925 ◽  
Author(s):  
E. W. Booth ◽  
D. J. Beaver

Abstract 1. Rubber dissolves approximately one per cent of hydrogen sulfide when saturated at room temperature. 2. All types of commercial accelerators are retarded in rate of vulcanization as a result of treatment with hydrogen sulfide, and the retardation is directly proportional to the hydrogen sulfide content. 3. The physical properties of mercaptobenzothiazole types of accelerators and diphenylguanidine are not permanently affected by hydrogen sulfide, but dithiocarbamates, thiuram sulfides, aldehydeamines and litharge are permanently affected. 4. Rubber compounds containing mercaptobenzothiazole types of accelerators or diphenylguanidine, which have been treated with hydrogen sulfide and then degassed in a vacuum oven, show normal rate of vulcanization. Compounds containing aldehydeamines, litharge or carbon black show permanent retarding, even after degassing. 5. Increased zinc oxide or sulfur has no appreciable effect on the retardation. 6. Little or no zinc sulfide is formed as a result of treatment with hydrogen sulfide. 7. Hydrogen sulfide treatment of rubber compounds retards the rate of combination of sulfur with rubber. 8. In no case did hydrogen sulfide treatment improve the physical properties of the vulcanizate.


1944 ◽  
Vol 17 (2) ◽  
pp. 451-474
Author(s):  
D. Parkinson

Abstract Carbon blacks can be grouped into different classes according to the way in which their fineness of division relates to different properties in rubber. Within any one class the principal properties vary in a regular manner with particle size. The normal class consists of the furnace carbons, Kosmos (Dixie)-40, Statex, the rubber-grade impingement carbons, and possibly, the color-grade impingement carbons. The subnormal classes consist of thermal carbons and acetylene and lamp blacks. Irrespective of the above classification, the properties which depend more on fineness of division than on other factors are rebound resilience, abrasion resistance, tensile strength and tear resistance. The lower limit of particle diameter for best tensile strength and tear resistance appears to be higher than that for abrasion resistance. B.S.I, hardness and electrical conductivity are properties which depend at least as much on other factors as on particle size. Stiffness (modulus) depends more on other factors than on particle size. Factors modifying the effects of particle size (or specific surface) include the presence of carbon-carbon structures and a reduction in strength of bond in rubber-carbon structures. Carbon black is thought to exist in rubber in four states: agglomerated, flocculated, dispersed, and bonded to the rubber molecules (the reënforcing fraction). Abrasion resistance is regarded as providing the only reliable measure of reënforcement.


1928 ◽  
Vol 1 (3) ◽  
pp. 458-464
Author(s):  
D. J. Beaver ◽  
T. P. Keller

Abstract The data presented herein show that in general the presence of oxygen on carbon black retards the rate of vulcanization in direct proportion to the amount of oxygen present and also decreases the maximum physical properties obtainable with a given amount of accelerator. The aging data show that the presence of this oxygen on the black increases the rate of aging as the amount of oxygen increases, but not in direct proportion to the per cent of this oxygen present. It can be concluded, therefore, that compounds which contain a small amount of oxygen, such as thermatomic, G black, or acetylene black, will give better aging stocks than compounds containing higher amounts of oxygen such as lampblack and standard channel blacks. No correlation could be found between the acetone extract, iodine adsorption, or oil adsorption, and the effect of these blacks on the rate of cure or aging.


2017 ◽  
Vol 744 ◽  
pp. 282-287
Author(s):  
Sarawut Prasertsri ◽  
Sansanee Srichan

This research aimed to develop the formulation of natural rubber filled with carbon black, silica and calcium carbonate for rubber calf nipple application. The reverse engineering was performed on the calf nipple product to analyze the rubber type and component by using Soxhlet extraction, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) techniques. Furthermore, mechanical properties were examined to act as benchmark for the rubber compound design. The results showed that rubber component in the nipple product was natural rubber, whereas two filler types revealed as carbon black and calcium carbonate with 10 and 35 of the total weight. In addition, rubber nipple showed the hardness of 46±1 Shore A and tensile strength of 5.3±0.60 MPa. From the investigation of the properties of developed rubber compounds in this work, it was found that the mechanical properties depended on type and content of filler. The required mechanical properties of vulcanizates were achieved at 20 phr of carbon black (N330), 20 phr of silica and 120 phr of calcium carbonate.


2018 ◽  
Vol 210 ◽  
pp. 02039
Author(s):  
Adam Skrobak ◽  
Vojtech Senkerik ◽  
Vaclav Janostik

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.


1939 ◽  
Vol 12 (2) ◽  
pp. 261-268
Author(s):  
A. G. Milligan ◽  
J. E. Shaw

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.


1994 ◽  
Vol 67 (2) ◽  
pp. 217-236 ◽  
Author(s):  
Timothy A. Okel ◽  
Walter H. Waddell

Abstract The effectiveness of predicting rubber performance based on measured silica physical properties in silica- and carbon black-filled compounds is presented for three rubber formulations: an off-the-road tire tread, a wire coat stock and a V-belt. Correlation and regression analyses were performed using SAS software for sixteen physical properties of thirteen precipitated silicas, and sixteen rubber compound performance characteristics of the three compounds. Silica physical properties studied include various measurements of surface area and structure, particle size, pH and impurities. Rubber performance characteristics studied include cure properties and physical properties such as stress/strain, tear strength, cut growth resistance, abrasion resistance and heat build-up. The present study confirms that silica surface area is the single best predictor of the effect that varying silica physical properties have on the physical performance of cured, carbon black-filled rubber compounds containing precipitated silica. Silica structure, as measured by DBP absorption and nitrogen or mercury pore volume, is a secondary predictor of certain rubber physical properties. The confidence limits of the predictions is dependent upon the concentration of precipitated silica used in the carbon black-filled rubber compound.


2012 ◽  
Vol 510-511 ◽  
pp. 532-539 ◽  
Author(s):  
M.A. Bashir ◽  
M. Shahid ◽  
R.A. Alvi ◽  
A.G. Yahya

Natural rubber (polymer designation cis-1-4 polyisoprene, is obtained from the sap ("latex") of several rubber-yielding plants (e.g.,HeveaBrasiliensisandPartheniaargentatum) by coagulation with chemicals, drying, electrical coagulation, and other processes. Foamy or sponge structure of natural rubber (NR) is very useful in aerospace and as auxetic materials (exhibiting negative poisons ratio) for use in application of homeland security.The main aim of this research to estimate the influence of carbon black on mechanical properties, curing and viscosity variation behaviors of the natural rubber based composites. Different amounts of carbon black were used along with other fillers. The influence of carbon black on curing behavior and mechanicalproperties of natural rubber foams was investigated at different feedingratios of the carbon black. The physical properties of the foamed NRs were then measured as a function of carbon blacks content. The mechanical properties of the foamed NRs such as tensile strength,strength at break and modulus,were gradually increased with increasingcarbon black content whereas elongation decreasedat break.


1938 ◽  
Vol 11 (3) ◽  
pp. 585-590
Author(s):  
A. H. Nellen ◽  
C. E. Barnett

Abstract A STUDY of the processing properties imparted by any pigment to a rubber compound is important in determining the most effective and economical type of pigment for a particular purpose. For example, in a truck tire carcass compound where zinc oxide may be the main pigment, in order to obtain the maximum quality this zinc oxide should be of the type which will give a soft uncured stock and free-flowing qualities so that the cords in the carcass may be thoroughly impregnated during the calendering and curing processes. Also, in a tread compound where channel black is the main pigment, that type of black which will allow faster incorporation into the rubber, faster extrusion, and better flowing qualities will result in manufacturing economies. In the case of both the zinc oxides and the carbon blacks it is essential that these desirable processing characteristics be obtained without losses in other properties, such as rate of cure, tensile strength, and abrasion resistance.


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