Silica Properties/Rubber Performance Correlation. Carbon Black-Filled Rubber Compounds

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.

2006 ◽  
Vol 79 (4) ◽  
pp. 610-620 ◽  
Author(s):  
H. H. Le ◽  
M. Tiwari ◽  
S. Ilisch ◽  
H-J. Radusch

Abstract In the present work, the effect of carbon black (CB) type on the electrical conductance of CB filled rubber compounds measured online in the internal mixer and the corresponding CB dispersion were investigated. The CB dispersion is strongly affected by the specific surface area and structure of CB which can be directly monitored by use of the online electrical conductance method. The effect of CB mixture ratio of a high conductive CB and a non-conductive one on the online electrical conductance was investigated for CB filled rubber compounds. By addition of a small amount of a high-conductive CB type into a non-conductive CB filled rubber compound, a characteristic online conductance - time characteristic is observed that is a result of the formation of a joint network of the two CB types. It could be shown, that such a characteristic is suitable to monitor the dispersion process of the non-conductive CB in the rubber compound.


1974 ◽  
Vol 47 (1) ◽  
pp. 231-249 ◽  
Author(s):  
E. S. Dizon ◽  
A. E. Hicks ◽  
V. E. Chirico

Abstract Fatigue is defined as decay caused by cyclic deformations at an amplitude less than necessary for fracture in one cycle. Such failures are initiated by flaws which act as stress concentrators. These flaws occur in the material either through mechanical or chemical action during service or through agglomeration of certain ingredients during mixing and fabrication. This paper deals with the latter process, where the nature and size of the flaws as well as the properties of the matrix are contingent on carbon black variables. Using the tearing energy concept of fatigue developed by Lake and Lindley, it was shown that the size of the flaw is primarily determined by carbon black particle size. On the other hand, the cut growth constant depends on carbon black structure. When translated to actual fatigue life using the Monsanto Fatigue-to-Failure Tester, these relationships mean that under constant strain conditions, compounds containing coarse carbons will have a significantly higher fatigue life than those with fine carbons. Under conditions of constant strain, higher structure carbons will impart a slight positive effect. However, under conditions of constant stress, the beneficial effects of structure become magnified. Other factors known to affect fatigue life were also considered. These are : set, stress relaxation, hysteretic energy dissipation, and flaw size distribution.


1988 ◽  
Vol 61 (5) ◽  
pp. 938-951 ◽  
Author(s):  
Nobuyuki Nakajima

Abstract The strain amplification is one of the recognized causes of the reinforcement of rubber by carbon black. Previously, we evaluated strain amplification in nonequilibrium, i.e., stress-strain measurements. Carbon-black-filled rubber compounds were used. In these examples, not only strain but also strain rate must be amplified, since it is a dynamic situation. Because the behavior of the gum matrix is strain-rate dependent, strain-rate amplification is also an important aspect of the rubber compound behavior. In this paper, we presented case studies of strain-rate amplification with several compounds involving variation of gum rubbers and carbon blacks.


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.


1972 ◽  
Vol 45 (1) ◽  
pp. 16-25 ◽  
Author(s):  
L. C. Coates ◽  
C. Lauer

Abstract The results of this study are conclusive. The ASTM D-2229 Test Method is not a reliable test for measuring adhesion of wire cords to rubber compounds. However, by using the basic design and modifying it, an accurate measurement of bond strength on a macroscopic level can be obtained. This test is insensitive for all practical purposes to compound physical properties and changes in cord diameter and embedded length—for both stranded and rod-like cords. It is also possible with this test to calculate the amount of stress that is exerted on the surface of the wire cord to determine the relationship between failing stress and the material strength of the rubber compound. Properly used, this new test should give the compounder a better tool to study the adhesion of compounds to metal.


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.


2003 ◽  
Vol 91 (1) ◽  
pp. 577-588 ◽  
Author(s):  
J. Léopoldès ◽  
C. Barrès ◽  
J. L. Leblanc ◽  
P. Georget

2003 ◽  
Vol 19 (3) ◽  
pp. 143-170 ◽  
Author(s):  
R. N. Datta

When sulfur vulcanized natural rubber compounds are exposed to a thermal ageing environment significant change in physical properties and performance characteristics are observed. These changes are directly related to modifications of the original crosslink structure. Decomposition reactions tend to predominate and thus leading to reduction in crosslink density and physical properties as observed during extended cure and when using higher curing temperatures. The decrease in network density is common when vulcanizates are subject to an anaerobic ageing process. However, in the presence of oxygen, the network density is increased with the main chain modifications playing a vital role. Over the years the rubber industry has developed several compounding approaches to address the changes in crosslink structure during thermal ageing. This paper gives a review of these compounding approaches. As with many formulation changes in rubber compounding, there is a compromise that must be made when attempting to improve one performance characteristic. For example, improving the thermal stability of vulcanized natural rubber compounds by reducing the sulfur content of the crosslink through the use of the more efficient vulcanization systems will reduce dynamic performance property such as fatigue resistance. The challenge is to define a way to improve thermal stability while maintaining dynamic performance characteristics.


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