A Measurement of Carbon Black Pellet Quality and its Significance

1966 ◽  
Vol 39 (4) ◽  
pp. 1081-1088 ◽  
Author(s):  
J. H. Atkins ◽  
B. B. Boonstra
Keyword(s):  
Carbon Black ◽  
Pellet Quality ◽  
Stress Strain ◽  
Pellet Strength ◽  
Short Period ◽  
New Instrument

Abstract A new instrument for measuring pellet quality is described which records the pellet strength of screened fractions of pellets. Samples large enough to be statistically representative can be measured in a relatively short period of time. The average pellet strength values, for each screened fraction, can be used to predict the incorporation time of the pellets into polymer. The maximum pellet strength values correlate with dispersion and by so doing, effect the stress—strain properties of the compounded elastomer.

Compressive Deformation and Energy Absorption Characteristics of Conductive Carbon Black Reinforced Microcellular EPDM Vulcanizates

2005 ◽  
Vol 24 (4) ◽  
pp. 209-222 ◽  
Author(s):  
S.P. Mahapatra ◽  
D.K. Tripathy
Keyword(s):  
Carbon Black ◽  
Compressive Stress ◽  
Energy Absorption ◽  
Filler Loading ◽  
Maximum Efficiency ◽  
Stress Strain ◽  
Blowing Agent ◽  
Compression Set ◽  
Rate Dependent ◽  
Conductive Carbon Black

Compressive stress-strain properties of unfilled and conductive carbon black (VulcanXC 72) filled oil extended EPDM (keltan 7341A) microcellular vulcanizates were studied as a function of blowing agent (density) and filler loading. With decrease in density, the compressive stress-strain curves for microcellular vulcanizates behaved differently from those of solid vulcanizates. The compressive stress-strain properties were found to be strain rate dependent. The log-log plots of relative density of the microcellular vulcanizates showed a fairly linear correlation with the relative modulus. The compression set at a constant stress increased with decrease in density. The efficiency of energy absorption E, was also studied as a function of filler and blowing agent loading. From the compressive stress-strain plots the efficiency E and the ideality parameter I, were evaluated. These parameters were plotted against stress to obtain maximum efficiency and the maximum ideality region, which will make these materials suitable for cushioning and packaging applications in electronic devices.

The Mechanism of Reinforcement

1945 ◽  
Vol 18 (2) ◽  
pp. 286-291 ◽  
Author(s):  
G. Goldfinger
Keyword(s):  
Carbon Black ◽  
Pigment Particle ◽  
Molecular Configuration ◽  
Stress Strain ◽  
Fundamental Study ◽  
Rubber Stock

Abstract In the fundamental study of the influence of reinforcing pigments, particularly carbon black on rubber, one of the great experimental difficulties is to establish the stress-strain properties of that fraction of the rubber stock which is between the pigment particles, and whose deformation, influenced by the presence of the pigment, is the quantity desired. This paper shows that it is not justifiable to assume that the rubber between pigment particles is equivalent in properties to the original gum stock without pigment, because the addition of pigment induces fractionation of the rubber in such a manner as to concentrate preferentially one molecular configuration around the pigment particle, and hence leave the rubber richer in some other configuration in the spaces between pigment particles.

Capillary Rheometry of Carbon-Black-Filled Butadiene—Acrylonitrile Copolymers

1975 ◽  
Vol 48 (4) ◽  
pp. 615-622 ◽  
Author(s):  
N. Nakajima ◽  
E. A. Collins
Keyword(s):  
Shear Rate ◽  
Carbon Black ◽  
Tensile Stress ◽  
Capillary Flow ◽  
Complex Viscosity ◽  
Appreciable Effect ◽  
Stress Strain ◽  
Capillary Rheometry ◽  
Strain Behavior ◽  
Acrylonitrile Copolymers

Abstract Capillary rheometry of carbon-black-filled butadiene—acrylonitrile copolymers at 125°C was performed over a wide shear rate range. The data were corrected for pressure loss in the barrel and at the capillary entrance, and for the non-Newtonian velocity profile (Rabinowitsch correction). No appreciable effect of pressure on viscosity was observed. The die swell values were very small, 1.1–1.4. This fact and the shape of the plots of shear stress vs. shear rate imply the presence of a particulate structure, which is probably built by carbon black surrounded with bound rubber. Unlike the behavior of raw amorphous elastomers, the steady-shear viscosity, the dynamic complex viscosity, and the viscosity calculated from tensile stress-strain behavior were significantly different from each other. That is, the capillary flow data indicated an alteration of the structure towards strain softening, and the tensile stress-strain behavior showed strain hardening, indicating retention of the structure up to the yield point. In the dynamic measurement, being conducted at very small strain, the structure is least disturbed. With unfilled elastomers essentially the same deformational mechanism was believed to be responsible in these three measurements, because the results can be expressed by a single master curve.

A Method to Resolve the Properties of Individual Phases in Carbon-Black-Loaded Elastomer Blends

1991 ◽  
Vol 64 (2) ◽  
pp. 234-242
Author(s):  
R. F. Bauer ◽  
A. H. Crossland
Keyword(s):  
Carbon Black ◽  
Large Deformation ◽  
Polymer Phase ◽  
Stress Strain ◽  
Strain Behavior ◽  
Stress Behavior ◽  
Strain Relationship ◽  
Deformation Stress ◽  
The Individual ◽  
Vulcanization Process

Abstract Properties of the individual phases in a 70/30 carbon-black-loaded BR/NR blend could be successfully resolved using large deformation stress-strain modelling. Since the dispersed NR phase of the example had a lower modulus than the continuous BR phase, the interaction between the blend phases could be modelled by a simple parallel coupling arrangement. The stress behavior of each individual carbon-black-loaded polymer phase was then determined with respect to strain using a specially derived stress-strain relationship. The blend components also have to be characterized with respect to state-of-cure by empirically establishing how the parameters in the stress-strain relationship vary with respect to cure. The properties of the phases in the blend are then determined by finding the combination of component parameters which precisely reproduce the stress-strain behavior of the blend. In the demonstration example of this paper, there was evidence of a significant amount of curative migration between phases during the vulcanization process.

Impact Resilience in Testing Channel Black

1937 ◽  
Vol 10 (4) ◽  
pp. 807-819 ◽  
Author(s):  
J. H. Fielding
Keyword(s):  
Carbon Black ◽  
Fundamental Property ◽  
Specification Tests ◽  
Stress Strain ◽  
Practical Test ◽  
Fundamental Properties ◽  
The Past ◽  
Strain Data ◽  
Great Merit

Abstract THE precise grading of carbon black has been a problem to rubber manufacturers for years. Empirical specification tests inherited from the paint and ink industries have been used extensively; although they may have great merit in predicting the behavior of a black in paint or ink, they generally tell very little of its value in rubber. Since neither these tests nor the usual stress-strain data showed any great differences that could be associated with type of carbon black, chemists have been inclined to believe in the past that the rubber grade of channel black was quite a uniform material, at least when used in mercaptobenzothiazole stocks. Among the tests which have been used recently in the grading of black is resilience of the cured stock as determined by an impact pendulum. Although superficially it seems to measure no fundamental property of the black, it is a very practical test from a laboratory standpoint and appears to be capable of at least rough correlation with more fundamental properties. It is not a new property; the fact that it is influenced by carbon black is not new; but its application to the separation of blacks within the range of rubber channel black is new, and this phase will be discussed here.

Reinforcement of Butyl with Carbon Black. II. Thermally vs. Chemically Oxidized Blacks

1964 ◽  
Vol 37 (4) ◽  
pp. 1034-1048 ◽  
Author(s):  
A. M. Gessler
Keyword(s):  
Carbon Black ◽  
Chemical Reactivity ◽  
Preceding Paper ◽  
Strain Curve ◽  
Convincing Evidence ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Carbon Particles ◽  
Vulcanized Rubber ◽  
Oxygen Functionality

Abstract The effect of oxidized blacks on the stress-strain properties and bound-rubber content of butyl and SBR was discussed in the preceding paper. Oxidized blacks, when compared with similar untreated blacks, were shown to have a greatly increased reinforcing capacity in butyl. Oxygen functionality on carbon black, it was therefore concluded, is essential in butyl to produce the chemical reactivity which is required between polymer and black if high-order reinforcement is to be obtained. Oxygen functionality on carbon black, it was also demonstrated, is not only not required for enhanced reinforcement in SBR, but it is in fact a deterrent, because it exerts severe restraining effects on the cure of the resulting vulcanizates as well. These interesting results were proposed to provide qualitative but convincing evidence that carbon-polymer bonding, which we believe is requisite to reinforcement, is achieved by different mechanisms in butyl and SBR. In butyl, the unique sensitivity of the stress-strain curve to reinforcing effects was used to speculate on the disposition of carbon blacks in “filled” and reinforced vulcanizates, respectively. With oxidized blacks, reinforcement effects were pictured as stiffening effects which, starting with the gum vulcanizates, caused the stress-strain curve to be shifted without intrinsic changes in its shape. The resulting “reinforced gum,” it was suggested, derived its physical characteristics from the fact that carbon black was included in the vulcanized rubber network. With untreated blacks, in “filled” systems, carbon black was pictured as being enmeshed or entangled in an independently formed vulcanized rubber network. The stiffening effects in this case were attributed to viscous contributions arising from steric restrictions which the occluded carbon particles were thought to impose on both initial movements and the subsequent orientation of network chains when the sample was extended.

Fatigue in Rubber. Part II

1939 ◽  
Vol 12 (2) ◽  
pp. 332-343 ◽  
Author(s):  
W. J. S. Naunton ◽  
J. R. S. Waring
Keyword(s):  
Carbon Black ◽  
Internal Friction ◽  
High Frequency ◽  
Strain Curve ◽  
Power Input ◽  
Viscous Resistance ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Wide Range ◽  
Rubber Part

Abstract 1. An apparatus is described for measuring the modulus and resilience of rubber over a wide range of frequencies. 2. These measurements can be made at any point in the stress-strain curve of the sample. 3. By increasing the power input, the same apparatus can be used to induce high frequency fatigue in the sample. 4. The earlier work with the torsion head apparatus has been confirmed, namely, that internal friction is greatest near zero strain. 5. High frequency resilience is more independent of degree of vulcanization than tripsometer resilience. 6. Modulus tends to increase with frequency. The effect is least with a rubber gum stock and is greater with compounds containing gas black. 7. Resilience decreases with frequency both in gum and gas black compounds. The decrease is more rapid in the gum compounds. 8. Viscous resistance decreases with frequency and becomes constant at higher frequencies. 9. The modulus of both rubber and Neoprene carbon black compounds decreases with fatigue. 10. The change in modulus with frequency in fatigued stocks is exactly analogous to the change before fatigue in rubber, but there is a slight divergence in the case of Neoprene.

Influence of Carbon Black on Processability of Rubber Stocks III. Extensional Viscosity

1978 ◽  
Vol 51 (4) ◽  
pp. 749-763 ◽  
Author(s):  
G. R. Cotten ◽  
J. L. Thiele
Keyword(s):  
Stress Relaxation ◽  
Carbon Black ◽  
Surface Area ◽  
Flow Curve ◽  
High Surface ◽  
Extensional Flow ◽  
Viscosity Coefficient ◽  
Extensional Viscosity ◽  
Relaxation Rates ◽  
New Instrument

Abstract A new instrument for measurement of extensional viscosity was designed and employed in the evaluation of SBR compounds containing carbon black and other non-black fillers. It was shown that carbon black filled rubbers generally do not reach steady-state viscosity ; the stress continues to increase with increasing strain up to the point of rupture, due to rapid orientation of molecular chains during extensional flow. The data was evaluated in terms of the Denn-Marrucci equation, and the effect of carbon black on the two adjustable parameters was found. It was found that higher carbon black loading or structure increases only the viscosity coefficient, i.e., it changes the relative level of the flow curve without changing its shape. On the other hand, an increase in surface area increases both the viscosity coefficient and the relaxation time, i.e., it increases the upward curvature of the flow curve. A very good correlation was observed between Mooney viscosity values and calculated viscosity coefficients. Some agreement was found between calculated relaxation times and the rates of stress relaxation for rubbers containing nonblack fillers, while in carbon black loaded stocks the observed differences in stress relaxation rates were too small to draw definite conclusions. The use of high surface area, low structure carbon black is recommended for applications where stiffening of the SBR compounds during extension is desired.

Latex Compounding of GR-S

1944 ◽  
Vol 17 (3) ◽  
pp. 711-718
Author(s):  
H. F. O'Connor ◽  
C. W. Sweitzer
Keyword(s):  
Carbon Black ◽  
Heat Resistance ◽  
High Temperatures ◽  
Room Temperature ◽  
Milling Time ◽  
Mixing Time ◽  
The Other ◽  
Stress Strain ◽  
Convenient Form ◽  
Latex Compounding

Abstract The more important findings in this study can be summarized as follows. (1) A satisfactory technique has been worked out for compounding GR-S in latex form, either with carbon alone or with carbon plus the other compounding ingredients. (2) Latex compounding of GR-S results in notable improvements in stress-strain properties. (3) Latex compounding of GR-S results in outstanding improvements in heat resistance properties, without any loss in rebound. (4) Latex compounding of GR-S results in lower modulus, higher elongation and higher subpermanent set. The increased set is significant, since it is accompanied by maintained rebound. Besides giving improved quality, latex compounding offers practical advantages and possibilities. These are listed below: (1) Latex compounding makes possible a reduction in the total milling time. This saving amounts to at least 10 per cent for carbon latex compounds and up to 50 per cent for complete latex compounds. The mixing time normally required in the Banbury is certainly not required. (2) Latex compounding makes possible cooler handling of the GR-S. Since the carbon is added to the latex at room temperature, no high temperatures are involved during its incorporation as in Banbury mixing. (3) Latex compounding makes possible cleaner handling of carbon, since it is added to the latex and is, therefore, mixed in the rubber before milling. If desired, the handling of carbon black could thus be transferred in toto to the polymer plants. This offers some interesting possibilities. (4) Latex compounding to the black crumb stage, followed by sheeting and baling, should provide a convenient and economical means for shipping black, particularly for transoceanic deliveries. There would also be important savings in containers. (5) The black latex crumb may provide a convenient form of compounded GR-S for extrusion and related operations.

The Stress-Strain Relation of Natural and Synthetic Rubbers

1944 ◽  
Vol 17 (4) ◽  
pp. 826-836
Author(s):  
A. J. Wildschut
Keyword(s):  
Carbon Black ◽  
General Formula ◽  
Stress Axis ◽  
Stress Strain ◽  
Vulcanized Rubber ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Axes Of Symmetry ◽  
Natural And Synthetic

Abstract It is shown that Hatschek's formula for the stress-elongation curve of rubber—better known as Ariano's formula—does not hold for normally vulcanized rubber. The observation has been made that the stress-elongation curves of natural and synthetic rubbers follow nonrectangular hyperbolae closely and practically up to the point of rupture. The axes of symmetry of these hyperbolae make angles of about 40° with the stress-axis in the case of pure-gum mixtures and about 30° for carbon black mixtures. A general formula has been derived which holds for all the rubbers investigated.

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