Resistivity of Unvulcanized Compounds of Rubber and Carbon Black

1977 ◽  
Vol 50 (1) ◽  
pp. 194-210 ◽  
Author(s):  
B. B. Boonstra
Keyword(s):  
Activation Energy ◽  
Electrical Resistivity ◽  
Carbon Black ◽  
Coefficient Of Variation ◽  
Absolute Temperature ◽  
Good Precision ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Rapid Monitoring ◽  
Coaxial Probe

Abstract 1. A coaxial probe has been developed which allows measuring electrical resistivity of uncured carbon black-rubber compounds with good precision (mean coefficient of variation 4%). 2. For a given compound the resistivity correlates well with the standard dispersion rating and thus can be used for rapid monitoring of dispersion at various stages of processing. 3. Resistivity may also serve as a check on the loading and type of black in a rubber compound. 4. The resistivity of uncured compounds is higher by a factor of 2–10 than the corresponding vulcanizate value. 5. The logarithm of the resistivity appears to be a linear function of the reciprocal of the absolute temperature. The apparent activation energy of conductance for SBR compounds is 14.7–29.3 kJ/mol, the higher values being found for the better dispersions. The activation energies of EPDM compounds were found to be approximately 50% higher than those of SBR.

Characterization of Snap-On Calf Nipple Product and Development of its Compound Formulation Based on Natural Rubber

2017 ◽  
Vol 744 ◽  
pp. 282-287
Author(s):  
Sarawut Prasertsri ◽  
Sansanee Srichan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Natural Rubber ◽  
Soxhlet Extraction ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Rubber Component

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.

Online Method for Characterization of the Homogeneity of Rubber Compounds Filled with Non-Conductive Carbon Black

2006 ◽  
Vol 79 (4) ◽  
pp. 610-620 ◽  
Author(s):  
H. H. Le ◽  
M. Tiwari ◽  
S. Ilisch ◽  
H-J. Radusch
Keyword(s):  
Carbon Black ◽  
Electrical Conductance ◽  
Rubber Compound ◽  
Mixture Ratio ◽  
Dispersion Process ◽  
Filled Rubber ◽  
Rubber Compounds ◽  
Conductance Method ◽  
Internal Mixer

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.

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
Keyword(s):  
Carbon Black ◽  
Physical Properties ◽  
Surface Area ◽  
Performance Characteristics ◽  
Rubber Compound ◽  
The Road ◽  
Precipitated Silica ◽  
Filled Rubber ◽  
Rubber Compounds ◽  
As Stress

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.

Strain-Rate Amplification of Carbon-Black-Filled Rubber Compounds

1988 ◽  
Vol 61 (5) ◽  
pp. 938-951 ◽  
Author(s):  
Nobuyuki Nakajima
Keyword(s):  
Carbon Black ◽  
Strain Rate ◽  
Case Studies ◽  
Rubber Compound ◽  
Strain Measurements ◽  
Rate Dependent ◽  
Filled Rubber ◽  
Rubber Compounds ◽  
Dependent Strain ◽  
Is Strain

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.

The Effects of Oil on Adhesion of Rubber

1974 ◽  
Vol 47 (1) ◽  
pp. 161-170 ◽  
Author(s):  
J. R. Beatty
Keyword(s):  
Carbon Black ◽  
Detrimental Effect ◽  
Rubber Compound ◽  
Good Adhesion ◽  
Adhesion Properties ◽  
New Approach ◽  
Rubber Compounds ◽  
Isoprene Rubber ◽  
Natural And Synthetic

Abstract It has been shown for poly(isoprene) rubber, both natural and synthetic, that the usual processing oils have essentially no effect on adhesion. The materials to which this statement apply are brass-plated wire, brass metal, steel, and R.F.L. dipped rayon, nylon, and polyester. The modulus of the rubber compound must be maintained constant by addition of carbon black to obtain these results. This work opens a new approach to the compounding of rubber compounds where good adhesion is necessary. It provides improved processing and reduced cost with no detrimental effect on adhesion properties.

Analysis of Resistivity in a Rubber Compound

1991 ◽  
Vol 64 (4) ◽  
pp. 501-509 ◽  
Author(s):  
D. Roig Fernández ◽  
A. J. Marzocca
Keyword(s):  
Electrical Resistivity ◽  
Carbon Black ◽  
Probability Model ◽  
Rapid Test ◽  
Rubber Matrix ◽  
Rubber Compound ◽  
Internal Factors ◽  
Tire Industry ◽  
Degree Of Dispersion ◽  
Electrical Conduction Mechanisms

Abstract In the tire industry, good dispersion of carbon black in the rubber matrix is very important to obtain optimum mechanical properties of the compound. Usually, this dispersion can be classified in macrodispersion (for particles bigger than 10 μm) and microdispersion (for those smaller than 10 μm). It is known that good microdispersion enables better fatigue resistance and wear. If it is desired to control the degree of dispersion of uncured compounds during the different processes in the factory, it would be necessary to have a simple and rapid test to do it. An appropriate method to detect different degrees of dispersion is based on the measurement of the electrical resistivity of the rubber compound with dc or ac. In recent years, different factors that affect the resistivity of the compounds were studied in several research programs. The internal factors include structure, size, and dispersion of carbon-black particles, the presence of other reinforcement (silica), and the polymer class. Other factors studied are external: mixing level, pressure, temperature, aging, and contact resistance. Boonstra showed that resistivity depends on the degree of dispersion of carbon black. In his paper, resistivity data are compared with the dispersion levels according to the Cabot rating with good correlation. Furthermore, there are several electrical conduction mechanisms that are proposed in the literature to explain experimental data. It is the purpose of this paper to present an improvement of the Boonstra device for the measurement of electrical resistivity of uncured compounds. The influence of temperature, pressure, aging, carbon black level, and time on the mill roll over the electrical resistivity were also studied. Finally, the results were analyzed by a probability model.

An Investigation of the Effect of Taurit Filling of Rubber Mixes for the Coating of Radial Lorry Tyre Breakers

2017 ◽  
Vol 44 (11) ◽  
pp. 21-24
Author(s):  
R.R. Mindubaev ◽  
A.M. Mokhnatkin ◽  
V.P. Dorozhkin ◽  
E.G. Mokhnatkina
Keyword(s):  
Carbon Black ◽  
Particle Distribution ◽  
Elastic Recovery ◽  
Dynamic Strength ◽  
Carbon Black Particle ◽  
Test Results ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Black Particle ◽  
Internal Mixer

The results of investigating the effect of the shungite analogue Taurit (grade TSD) on the properties (measured on an RPA 2000 instrument) of a breaker rubber mix and of a rubber compound based on synthetic isoprene rubber SKI-3 are set out. Different methods of introducing Taurit have been tested: 10 parts into the rubber at the stage of its production; 10 parts into the standard rubber mix at the first stage of mixing; 10 parts into the rubber subjected to preliminary mechanical plasticisation in a laboratory internal mixer at a temperature of 100°C. The introduction of Taurit into the rubber in small quantities in order to reduce the proportion of rubber constituent in the rubber mix has also been tested. The test results have been compared with results for standard rubber mixes and rubber compounds. When Taurit is introduced into rubber at the stage of its production, the cohesive strength of the rubber mix and the rate of its vulcanisation and also the dynamic modulus components G′ and G″ are increased. When Taurit is introduced into plasticised rubber, again G′ and G″ are increased, there is an increase in plasticity, and the elastic recovery of the rubber mix is reduced. The breaker rubber compound from this mix has the best adhesion to metal cord and the highest dynamic strength. Data on the Payne effect indicate a better carbon black particle distribution when Taurit is introduced into the rubber at the stage of its production. Reduction in the proportion of rubber constituent in the rubber mix leads to a deterioration in the carbon black particle distribution.

Resistivity of Rubber as a function of Mold Pressure

1988 ◽  
Vol 61 (5) ◽  
pp. 828-841 ◽  
Author(s):  
Corley M. Thompson ◽  
T. W. Besuden ◽  
L. L. Beumel
Keyword(s):  
High Pressure ◽  
Electrical Resistivity ◽  
Carbon Black ◽  
Kinetic Data ◽  
Careful Consideration ◽  
Molding Pressure ◽  
Covalent Bonds ◽  
Cure Cycle ◽  
Effect Of Pressure ◽  
Rubber Compounds

Abstract For this N550 carbon black, loaded over a narrow but typically used range, high molding pressure caused a decrease in electrical resistivity of several orders of magnitude. The earlier in the cure cycle the high pressure was applied, the greater was the decrease in resistivity. A suggested mechanism for the effect is the formation of covalent bonds between carbon-black particles that are pushed into closer proximity by the high mold pressure. This postulate is supported by the limited kinetic data available. Clearly, pressure applied to a rubber sample during molding must be given as careful consideration as the loading of carbon black when materials requiring high resistivities are prepared. Although it has not been pursued in this work, the effect of pressure on the electrical resistivity of conductive rubber formulations may be significant. Further work underway is addressing the effect of mold pressure on the electrical resistivity of other rubber compounds as well as loadings of some other types of carbon black.

Study on the Effect of the Temperature Rise of Rubber Compound on Tread Rubber Quality during Mixing Process

2013 ◽  
Vol 750-752 ◽  
pp. 806-810
Author(s):  
Ke Juan Chen ◽  
Sha Xu ◽  
Da Liang Xu
Keyword(s):  
Carbon Black ◽  
Temperature Rise ◽  
Process Condition ◽  
Process Conditions ◽  
Rubber Compound ◽  
Rotor Speed ◽  
Two Stage ◽  
Rubber Compounds ◽  
Mooney Viscosity ◽  
Internal Mixer

With the method of two-stage mixing, two different tread rubbers have been mixed in internal mixer under the different process conditions. After the experiments, test the temperature rise of rubber compound, mooney viscosity and carbon black disperisity. Study the effect of process condition change on the temperature rise of two kinds of rubber compounds and analyze the relationships between the rubber temperature rise and mooney viscosity, carbon black dispersity. The study finds that the temperature rise of rubber compound has a relationship with the rotor speed of internal mixer, rubber viscosity and filling factors, but when the temperature rise of rubber compound is steady, the carbon black dispersity of rubber compound also can be steady. After two-stage mixing, carbon black dispersity of rubber compounds have been improved obviously. These results also imply that rotor speed of internal mixer and filling factor are very important to carbon black dispersity of rubber compounds.

Sign in / Sign up

Export Citation Format

Share Document