Carbon Blacks and Their Use in Rubber. III—Aging Effects

1928 ◽  
Vol 1 (3) ◽  
pp. 475-484
Author(s):  
L. B. Cox ◽  
C. R. Park
Keyword(s):  
Zinc Oxide ◽  
Carbon Black ◽  
Stearic Acid ◽  
Weight Increase ◽  
Aging Effects ◽  
Carbon Blacks ◽  
Aging Properties ◽  
Good Agreement

Abstract The aging properties of compounded rubber stocks are affected by the carbon black which is used. The order of increasing superiority for the blacks tried is Super Spectra, Micronex, Charlton, Goodwin, and Thermatomic. The order of increasing superiority of accelerators is diphenylguanidine, hexamethylenetetramine, ethylidene-aniline, mercaptobenzothiazole. The last two are put in this order mainly because of the inferior original properties of ethylidene-aniline. Results of tensile, abrasion, and weight increase tests are in reasonably good agreement. The effect of acidity in any compounding material is neutralized in a stock containing zinc oxide. Stearic acid is without effect upon aging properties of cured rubber.

Plasma Polymerized Primers for Rubber to Metal Bonding: Characterization of the Interphase

1995 ◽  
Vol 385 ◽  
Author(s):  
Y. M. Tsai ◽  
F. J. Boerio ◽  
Dong K. Kim
Keyword(s):  
Zinc Oxide ◽  
Free Radicals ◽  
Carbon Black ◽  
Stearic Acid ◽  
Natural Rubber ◽  
Rubber Compound ◽  
Carbonyl Groups ◽  
Double Bonds ◽  
Metal Bonding

ABSTRACTPlasma polymerized acetylene films contained mono- and di-substituted acetylene groups, aromatic groups, and carbonyl groups which resulted from reaction of residual free radicals with oxygen when the films were exposed to the atmosphere. There was some evidence for formation of acetylides in the interphase between the films and the substrates. Reactions occurring in the interphase between the plasma polymerized films and natural rubber were simulated using a model rubber compound consisting of a mixture of squalene, zinc oxide, carbon black, sulfur, stearic acid, diaryl-p-diphenyleneamine, and N,N-dicyclohexylbenzothiazole sulfenamide (DCBS). Zinc oxide and cobalt naphthenate reacted with stearic acid to form zinc and cobalt stearates. The stearates reacted with the benzothiazole sulfonamide moiety of DCBS and with sulfur to form zinc and cobalt accelerator complexes and perthiomercaptides. The complexes and perthiomercaptides reacted with squalene and the plasma polymer to form pendant groups which eventually disproportionated to form crosslinks between squalene and the primer. Migration of double bonds during reaction of the model rubber compound with the films resulted in formation of conjugated double bonds in squalene.

Dispersion of Channel Gas Black in Rubber. Effect of Stearic Acid and Other So-called Dispersing Agents

1935 ◽  
Vol 8 (3) ◽  
pp. 470-482
Author(s):  
C. R. Park ◽  
V. N. Morris
Keyword(s):  
Zinc Oxide ◽  
Fatty Acid ◽  
Carbon Black ◽  
Stearic Acid ◽  
Convincing Evidence ◽  
Zinc Stearate ◽  
Surface Forces ◽  
Dispersing Agent ◽  
Principal Effect ◽  
Dispersing Agents

Abstract THE completeness of wetting of carbon black by rubber, the consequent state of dispersion of the black, and the effect of the surface forces in the development of reënforcement of the rubber have been the subjects of much deliberation and experimentation. Of special interest has been the effect of stearic acid upon the dispersing power of rubber for carbon black. On the basis of Green's observation (6) that the dispersion of zinc oxide which had previously flocculated in kerosene resulted in a pronounced softening of the mixture, Goodwin and Park (5) concluded that stearic acid has little effect upon the dispersion of carbon black in rubber. They pointed out that stearic acid has a slight softening action in uncured stock and in cured stock containing no zinc oxide, and that the addition of fatty acid to a stock containing no zinc oxide affects its physical properties adversely. Although they considered that these facts furnished slight indications of a dispersing effect by the stearic acid, these authors offered no convincing evidence of the dispersing effect of stearic acid on carbon black in rubber. For various reasons, including the fact that the plasticity of uncured black stocks is not materially affected by the presence of zinc stearate, Goodwin and Park also concluded that zinc stearate is not a dispersing agent for blacks. In fact, they postulated that the effect of zinc stearate, if any, is to decrease the wetting of the black by the medium and hence to cause flocculation. Since the combined addition of zinc oxide and stearic acid to a rubber-sulfur mix results in an improvement in properties, these investigators were finally led to the conclusion that the principal effect of these soap-forming agents in a carbon black stock is on the curing properties of the rubber itself rather than on the dispersion of the black.

Some Observations on Carbon Black

1930 ◽  
Vol 3 (1) ◽  
pp. 111-121
Author(s):  
C. M. Carson ◽  
L. B. Sebrell
Keyword(s):  
Zinc Oxide ◽  
Carbon Black ◽  
Adsorptive Capacity ◽  
Carbon Blacks ◽  
Vulcanized Rubber ◽  
Rubber Cement

Abstract Different carbon blacks have certain definite effects upon the vulcanized rubber stocks with which they are mixed. The experiments described herein may be grouped under four main heads: (1) adsorption, (2) effect of heat, (3) reaction with sulfur and zinc oxide, and (4) dispersion or rate of settling. The adsorptive capacity of the black is a measure of the rate of cure of the rubber mix, low-adsorptive blacks giving a faster curing stock than high-adsorptive blacks. An indication of the stiffening action of a carbon black may be secured by measuring the amount of carbon dispersed in a thin rubber cement which cannot be centrifuged out in a given time. The effect of temperatures from 500° to 1200° C. on carbon blacks is to render them highly adsorptive and also to give a rubber mix which cures faster and has a higher modulus. The reaction of carbon blacks with sulfur and zinc oxide in boiling xylene liberates a substance having accelerating properties in a pure gum mix.

Measurement of Average Particle Size of Fine Pigments

1932 ◽  
Vol 5 (2) ◽  
pp. 202-215 ◽  
Author(s):  
S. D. Gehman ◽  
T. C. Morris
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Carbon Black ◽  
Wave Length ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Carbon Blacks ◽  
Count Method

Abstract A method of obtaining excellently dispersed suspensions of rubber pigments of accurate concentration is described in which the pigment is milled into rubber and the stock then dissolved in a solvent. The average particle sizes of carbon blacks measured by the Zsigmondy count method were found to range from 0.061μ for rubber gas black to 2.22μ for the coarsest one measured. The zinc oxide pigments had average particle sizes from 0.076μ to 0.57μ.. Measurements on several other pigments of interest are included. Because of the high visibility in the ultra-microscope, this method gives smaller values for average particle size than the photomicrographic methods. The results have been used to calibrate a microturbidimeter of the extinction type for use in measuring average particle size. Curves are included showing how the turbidities of suspensions of zinc oxide and carbon black vary with the average particle size, concentration, and wave length of light used.

The Heat Conductivity of Rubber

1940 ◽  
Vol 13 (2) ◽  
pp. 361-374 ◽  
Author(s):  
L. S. Frumkin ◽  
Yu B. Dubinker
Keyword(s):  
Thermal Conductivity ◽  
Zinc Oxide ◽  
Carbon Black ◽  
Temperature Change ◽  
Heat Conductivity ◽  
Carbon Blacks ◽  
Increase With Increase ◽  
Vulcanization Process

Abstract 1. In rubber technology, the important factor is the heat conductivity of rubber mixtures, which is characterized by the rate of temperature change of the inner layers. 2. The method proposed makes it possible to compare the heat conductivities of rubber mixtures. 3. The heat conductivities of all types of rubber mixtures increase with increase in temperature. 4. Addition of zinc oxide in the usual proportions decreases the heat conductivity of mixtures containing no carbon black; in mixtures containing carbon blacks the addition of zinc oxide increases slightly their heat conductivty. It follows that the addition of zinc oxide for the acceleration of the vulcanization process has an insignificant influence on thermal conductivity. 5. With increasing additions of carbon black up to 25 per cent by weight of the rubber mixtures result the heat conductivity increases; but with further increases in the percentage of carbon blacks the heat conductivity decreases. 6. Rubber mixtures of the same composition but containing different kinds of carbon black show different heat conductivities. The lowest heat conductivity was found in rubber mixtures containing P-33 carbon black, followed in increasing order of heat conductivity by mixtures with Mai˘kop, Gastex, Thermax, Kudinov and Yaroslav carbon blacks. Thus lampblacks have a greater effect on the heat conductivity of rubber mixtures than do gas blacks.

Extraction and identification of fillers and pigments from pyrolyzed rubber and tire samples

1996 ◽  
Vol 54 ◽  
pp. 174-175
Author(s):  
P. Sadhukhan ◽  
J. B. Zimmerman
Keyword(s):  
Zinc Oxide ◽  
Electron Microscope ◽  
Carbon Black ◽  
Natural Rubber ◽  
Transmission Electron Microscope ◽  
Rolling Resistance ◽  
Synthetic Polymers ◽  
Nitrogen Atmosphere ◽  
Transmission Electron ◽  
Curing Agents

Rubber stocks, specially tires, are composed of natural rubber and synthetic polymers and also of several compounding ingredients, such as carbon black, silica, zinc oxide etc. These are generally mixed and vulcanized with additional curing agents, mainly organic in nature, to achieve certain “designing properties” including wear, traction, rolling resistance and handling of tires. Considerable importance is, therefore, attached both by the manufacturers and their competitors to be able to extract, identify and characterize various types of fillers and pigments. Several analytical procedures have been in use to extract, preferentially, these fillers and pigments and subsequently identify and characterize them under a transmission electron microscope.Rubber stocks and tire sections are subjected to heat under nitrogen atmosphere to 550°C for one hour and then cooled under nitrogen to remove polymers, leaving behind carbon black, silica and zinc oxide and 650°C to eliminate carbon blacks, leaving only silica and zinc oxide.

scholarly journals Interpreting 14C Measurements on 3rd–4th Century AD Iron Artifacts from Nydam, Denmark

Radiocarbon ◽  
2019 ◽  
Vol 61 (5) ◽  
pp. 1517-1529
Author(s):  
C Matthias Hüls ◽  
John Meadows ◽  
Andreas Rau
Keyword(s):  
Isotopic Composition ◽  
Combustion Temperature ◽  
Peat Bog ◽  
Iron Production ◽  
Aging Effects ◽  
Carbon Dissolution ◽  
Fossil Carbon ◽  
Common Effect ◽  
Iron Artifacts ◽  
Good Agreement

ABSTRACTRadiocarbon (14C) ages were determined for 10 iron samples from the war booty offering site in the Nydam peat bog (SE Denmark), and compared to archaeologically inferred periods of deposition. Additional 14C measurements were carried out for modern iron standards made with charcoal of known isotopic composition to evaluate possible effects of handling. Modern iron standards give depleted 14C concentrations, compared to the initial charcoal 14C composition, and may indicate carbon fractionation effects during carbon dissolution in the iron lattice. Further studies are needed to verify if this is a common effect during iron production. 14C dating of two swords and one ax head are in comparatively good agreement with expected deposition times and indicate only small old-wood effects. In contrast, 14C dating of iron rivets from the Nydam (B) oak boat proved difficult due to corrosion with siderite (FeCO3) and conservation with wax. A step-combustion procedure was applied, using a low (∼570–600°C) temperature prior to the high (∼970–1000°C) combustion temperature for carbon extraction, aiming to remove siderite and wax before collecting the original carbon dissolved in the iron lattice. Nevertheless, measured 14C ages of the iron rivets differ by about 200–300 years from the dendro-date of the Nydam (B) oak boat they belong to, indicating persisting aging effects (e.g. old-wood, contamination with fossil carbon added during iron making and/or handling prior 14C dating). Also, a possible recycling of older iron cannot be excluded.

Ionic Crosslinking of Carboxylated SBR

1983 ◽  
Vol 56 (5) ◽  
pp. 942-958 ◽  
Author(s):  
Kyosaku Sato
Keyword(s):  
Zinc Oxide ◽  
Carbon Black ◽  
Elevated Temperatures ◽  
Ion Clusters ◽  
Ionic Crosslinking ◽  
Reinforcing Fillers ◽  
Ionic Bonds ◽  
Tan Δ ◽  
And Shifts ◽  
Ionic Crosslinks

Abstract 1. Ionic bonding of carboxylated SBR with zinc oxide is detectable by means of measurements of the temperature dependence of tan δ. There is an α peak in the region of 60°C at 3.5 Hz. The position and shape of the α peak are strongly dependent on the state of cure of the vulcanizates. Without permanent crosslinking, the α peak is a plateau; as the crosslink density increases, the α peak becomes sharper and shifts to lower temperatures. The presence of carbon black causes the α peak to shift to higher temperatures, regardless of the presence of permanent crosslinks. 2. Ionic bonds in carboxylated SBR reacted with zinc oxide are in the form of ion clusters which function as crosslinks at room temperature. The ionic crosslinks provide carboxylated SBR with high tensile strength in the absence of reinforcing fillers. The presence of carbon black causes the 300% modulus to increase. The ionic crosslinks are labile, and the strength is lost at moderately elevated temperatures. A mixed cure system consisting of both sulfur and zinc oxide provides higher heat resistance than either of the single cure systems.

A Carbon Black Structure-Concentration Equivalence Principle. Application to Stress-Strain Relationships of Filled Rubbers

1971 ◽  
Vol 44 (1) ◽  
pp. 199-213 ◽  
Author(s):  
Gerard Kraus
Keyword(s):  
Carbon Black ◽  
Primary Structure ◽  
Equivalence Principle ◽  
Chemical Activity ◽  
Cross Linking ◽  
Surface Chemical ◽  
Deformation Structure ◽  
Carbon Blacks ◽  
Filled Rubbers ◽  
Dependent Factor

Abstract It is shown that various modulus values of carbon black reinforced rubber are functions of the product of the actual black loading and a structure dependent factor. The structure factor appears to be a linear function of the so-called 24M4 value of the dibutylphthalate absorption and is independent of elongation, temperature, and degree of cross-linking over the ranges covered by the data reported. An interpretation of the results is offered based on the idea of polymer occluded in the interstices of primary structure aggregates and thereby shielded from deformation. Structure-concentration equivalence can only be demonstrated with carbon blacks differing in (primary) structure alone. Deviations are observed whenever the carbon blacks compared vary significantly in specific surface area and surface chemical activity.

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