Microstructural Variations in Commercial Carbon Blacks

1968 ◽  
Vol 41 (2) ◽  
pp. 356-372 ◽  
Author(s):  
W. M. Hess ◽  
L. L. Ban ◽  
F. J. Eckert ◽  
V. Chirico
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Carbon Black ◽  
Crystallite Size ◽  
Surface Activity ◽  
Chain Structure ◽  
Rate Of Change ◽  
Degree Of Crystallinity ◽  
Crystallite Orientation ◽  
Carbon Blacks

Abstract Conventional and diffracted beam electron microscopy can be used to resolve the ultimate crystallite units in standard and heat treated carbon blacks. They are very sensitive in the detection of small differences in crystallite size and orientation. Combined with x-ray diffraction methods and conventional vulcanizate testing, high resolution electron microscopy appears to be a useful and practical means to study carbon black surface activity. All commercial blacks appear to conform in part to the Heckman and Harling concentric crystallite model. Surface activity appears to be related to the extent of this alignment; the less the tangential orientation of the graphite layer planes to the surface, the greater the surface activity. Heating carbon blacks in an inert atmosphere for varying times and temperatures (850 to 1400° C) causes a gradual depression of surface activity with increasing treatment severity, defined by increases in the size and concentric orientation of surface crystallites. At no time was the effect of carbon black on vulcanizate properties changed significantly by heat treatment without disrupting the initial orientation of surface crystallites. Carbon blacks differ in the rate of change of crystallite orientation in response to heat treatment. The initial degree of crystallinity, porosity, and surface volatile content all appear to affect the rate of crystallite orientation and growth. Increases in average crystallite height, Lc, are a good measure of effects of heat treatment in excellent agreement with changes in surface crystallite size and orientation observed with the electron microscope. Commercial ISAF carbon blacks of varied structure have relatively minor differences in surface crystallite orientation, indicating small differences in surface activity. The higher modulus and treadwear associated with the use of high structure blacks appear to be predominantly a result of the chain structure itself. Further evidence was obtained showing that black structure and surface activity are independent properties each of which can have a significant influence on vulcanizate properties such as modulus, treadwear, and hysteresis.

scholarly journals Влияние температуры фотонного отжига на структурные и оптические свойства пленок ZnO, синтезированных методом дуального магнетронного распыления

2019 ◽  
Vol 53 (2) ◽  
pp. 267
Author(s):  
С.В. Зайцев ◽  
В.С. Ващилин ◽  
В.В. Колесник ◽  
М.В. Лимаренко ◽  
Д.С. Прохоренков ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Crystallite Size ◽  
Annealing Temperature ◽  
Optical Transmittance ◽  
Degree Of Crystallinity ◽  
Zno Films ◽  
Gas Atmosphere ◽  
Oxygen Gas ◽  
Microstructure Density ◽  
The Degree Of Crystallinity

AbstractZinc-oxide films 1.4 μm in thickness are deposited onto glassy substrates by the dual magnetron-assisted sputtering of zinc targets in an argon and oxygen gas atmosphere. The dependences of the structural and optical characteristics of the ZnO films on the temperature of postdeposition photonic annealing are studied. It is established that an increase in the annealing temperature yields an increase in the degree of crystallinity of the films. Electron microscopy shows that the deposited ZnO coatings are columnar in structure and the microstructure density and crystallite size increase upon annealing. It is found that, at an annealing temperature of 450–650°C, the optical transmittance increases to >90% in the spectral range 400–1100 nm. The experimental results show that the temperature of vacuum photonic annealing has the most profound effect on the final properties of ZnO coatings.

Structure and Properties of Loaded Rubber Mixtures. X. Alteration of Carbon Black Structures by Heat Treatment

1953 ◽  
Vol 26 (4) ◽  
pp. 821-831 ◽  
Author(s):  
B. A. Dogadkin ◽  
K. Pechkovskaya ◽  
Ts Mil'man
Keyword(s):  
Heat Treatment ◽  
Carbon Black ◽  
Electric Resistivity ◽  
Structure And Properties ◽  
Prolonged Heating ◽  
Carbon Blacks ◽  
Exponential Law ◽  
Carbon Structures ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds

Abstract 1. Raising the temperature of vulcanizates containing carbon black causes changes in the carbon structures, which can be estimated by the value of specific electric resistivity ρ and the index n in the equation: I=cVn, relating the strength of the current I with the voltage V. 2. These changes are nearly independent of the type of rubber and are governed chiefly by the type of carbon black. 3. The change of electric resistivity of vulcanizates with temperature follows an exponential law, and can be expressed by the equation : ρt=ρ0 eαt. 4. The sign of the coefficient α is negative for vulcanizates containing channel carbon black, and positive for those containing nozzle black or lamp black. 5. Heating of vulcanizates (up to 100°) for 30 minutes causes destruction of the nozzle black and lamp black particles, but causes little apparent destruction of channel black structures. 6. Prolonged heating (10 hours or more) at temperatures above 60° C causes destruction of the particles of all the carbon blacks studied. This detruction is more extensive in the case of nozzle and lamp blacks than in the case of channel black. 7. During heat treatment of mixtures containing channel black, it is chiefly the carbon-rubber bonds that are destroyed (the index n decreases); whereas in mixtures containing nozzle, furnace and lamp blacks, it is chiefly the carbon-carbon bonds that are destroyed (the index n increases). 8. The higher the temperature during deformation and relaxation, the greater is the degree of restoration of the carbon structures which are destroyed during deformation. 9. The degree of restoration of the carbon structures under identical conditions of deformation and relaxation of vulcanizates containing nozzle black is greater than that of corresponding vulcanizates containing channel black.

scholarly journals Surface modification of nano-sized carbon black for reinforcement of rubber

2019 ◽  
Vol 8 (1) ◽  
pp. 405-414 ◽  
Author(s):  
Maochuan Gao ◽  
Feng Zheng ◽  
Jinjia Xu ◽  
Shangyong Zhang ◽  
Sanjana S. Bhosale ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Carbon Black ◽  
Surface Activity ◽  
Inverse Gas Chromatography ◽  
Dibutyl Phthalate ◽  
Performance Test ◽  
Heating Surface ◽  
Treatment Temperature ◽  
Industrial Carbon ◽  
Carbon Black Nanoparticles

Abstract The standard sample IRB7# of nano-sized carbon black was reated by different methods, including washing by alcohol, toluene, water, the emulsion of toluene and water, and heating. Surface activity of the obtained nanoparticles was measured using inverse gas chromatography. The results showed that the dispersion free energy could be significantly increased after heating. The surface activity of three kinds of industrial carbon black was studied after heat treatment at different temperature. The results indicated that surface activity, iodine adsorption number and nitrogen surface area values of carbon black nanoparticles increased with the increase of temperature. However, the dibutyl phthalate adsorption value maintained nearly constant. The performance test of rubber showed that with the increasing heat treatment temperature of carbon black, 300% modulus of rubber increased before 450°C and decreased after 450°C.

Reactions of Polymers in Bulk. I. Influence of Fillers on the Degree of Crosslinking of Natural Rubber

1962 ◽  
Vol 35 (3) ◽  
pp. 563-571 ◽  
Author(s):  
J. Janacek
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Specific Surface ◽  
Contact Surface ◽  
Chemical Nature ◽  
Chain Structure ◽  
Filler Concentration ◽  
Carbon Blacks

Abstract The relation between the degree of crosslinking determined by means of swelling and the theoretical total contact surface of rubber to carbon black was investigated with vulcanizates of two elastomers which were cured by various vulcanization methods and using various concentrations—even extremely high ones—of carbon blacks with different specific surface, degrees of chain structure and chemical activities. A constant, α, the magnitude of which generally depends upon the degree of agglomeration of the carbon blacks and on the chemical nature of their surface as well as on the polymers used and the vulcanization method, but which is practically unrelated to the filler concentration, has been proposed to express the relative crosslinking activity of carbon blacks.

ADSORPTION STUDIES ON A SERIES OF HEAT TREATED SHAWINIGAN ACETYLENE CARBON BLACKS

1957 ◽  
Vol 35 (12) ◽  
pp. 1542-1554 ◽  
Author(s):  
J. M. Holmes ◽  
R. A. Beebe
Keyword(s):  
Heat Treatment ◽  
Carbon Black ◽  
Low Oxygen ◽  
Carbon Blacks ◽  
Heat Treated ◽  
Treated Carbon ◽  
Derivatives Of ◽  
Graphitic Material ◽  
Acetylene Carbon ◽  
Acetylene Carbon Black

An experimental study has been made of the adsorption of a nitrogen, sulphur dioxide, carbon dioxide, and ammonia on Shawinigan acetylene carbon black and several derivatives of this material produced by heat treatment up to temperatures of 3000°. The effect of the heat treatment of the Shawinigan carbon black on its adsorption of the polar and non-polar gases studied is compared with the behavior of other heat treated carbon blacks. In particular, the effect of the low oxygen content of the Shawinigan black is considered. The isosteric heats of adsorption for ammonia on the most highly graphitized material (Shawinigan 3000) have been calculated. The results are in general agreement with previous calorimetric work of this laboratory. A special type of hysteresis for the system ammonia – Shawinigan black has been observed. This may be due to a reversible swelling of the graphitic material.

Identifying and quantifying amorphous and crystalline content in complex powdered samples: application to archaeological carbon blacks

2016 ◽  
Vol 49 (2) ◽  
pp. 585-593 ◽  
Author(s):  
Sophie Cersoy ◽  
Pauline Martinetto ◽  
Pierre Bordet ◽  
Jean Louis Hodeau ◽  
Elsa Van Elslande ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Organic Matter ◽  
Carbon Black ◽  
Methodological Approach ◽  
Mixed Phase ◽  
Carbon Blacks ◽  
Heterogeneous Samples ◽  
Scanning Electron ◽  
Black Materials

Carbon black materials have been frequently used from prehistory as pigments for drawings and paintings and also as dyes, inks and cosmetics, since they are easy to make by burning organic matter. However, the carbonaceous phases they form are often ill-ordered and not easy to characterize. Five carbon black Roman micro samples found in vessels in houses in Pompeii were studied. These precious powders correspond to mixed phase samples that contain both crystalline and ill-ordered components. Here, a methodological approach that accomplishes the identification, quantification and mapping of the different phases in these heterogeneous samples using synchrotron-based techniques is proposed. The results were compared with those from scanning electron microscopy. Information about the nature of the mixtures and the origin of carbon black pigments is obtained. The use of charred vegetable materials is concluded, independently of the shape and the nature of the container.

The Nature and Activity of Carbon Black Surfaces

1950 ◽  
Vol 23 (3) ◽  
pp. 625-634 ◽  
Author(s):  
W. R. Smith ◽  
W. D. Schaeffer
Keyword(s):  
Carbon Black ◽  
Surface Activity ◽  
Chemical Properties ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
High Concentration ◽  
Equal Concentration ◽  
Heats Of Adsorption ◽  
Carbon Blacks ◽  
Chemisorbed Oxygen

Abstract While the electron microscope and adsorption isotherm techniques for evaluating the particle size and surface area of carbon blacks have been particularly valuable in interpreting their behavior in rubber, they also emphasize the fact that reinforcement cannot be interpreted solely on this basis. The activity or nature of the surface must also be considered. Heats of adsorption offer a means of evaluating surface activity. The differential heats of adsorption have been measured by precision calorimetry for nitrogen and a series of C4 hydrocarbons on a group of carbon blacks of varying reinforcing ability. Initial sites of high activity were detected. Surface activity decreases with increasing surface coverage. The magnitude of the initial heats parallels the reinforcing properties of the blacks studied. The surface activity and reinforcing ability of an MPC black was found to be greatly reduced by high temperature treatment. These effects were not influenced by the chemical nature of the surface, i.e., the presence of chemisorbed oxygen or volatile substances. In a further phase of this study, the nature of the surface oxide complexes present on carbon blacks has been studied by means of their emission band spectra in a special vacuum discharge tube. Aldehyde and carboxyl radicals were observed in high concentration. Hydroxyl radicals were also present in nearly equal concentration. These data offer a satisfactory interpretation of the pH properties of carbon black and also should prove of value in interpreting other chemical properties.

Characterization of Dispersions

1991 ◽  
Vol 64 (3) ◽  
pp. 386-449 ◽  
Author(s):  
W. M. Hess
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Black ◽  
Phase Distribution ◽  
Automated Image Analysis ◽  
Carbon Blacks ◽  
Transmission Electron ◽  
Vehicle Systems ◽  
Scanning Electron

Abstract The methods of pigment dispersion analysis have been reviewed in regard to their application to rubber, plastics, and other vehicle systems. The characteristics of dispersions have been divided into three categories: (1) agglomeration (2) microdispersion (networking) and (3) polymer-phase distribution. Stylus roughness measurements on cut surfaces offer the combination of simplicity and speed of operation with high accuracy and precision for measuring pigment agglomeration in elastomer systems of known composition. This method may also be applied to the surface of thin plastic extrudates. However, optical analyses of thin cryosections are preferred for most plastics or unknown rubber compounds containing high loadings of carbon black. X-radiography is generally preferable for the analysis of inorganic agglomeration in most polymeric vehicle systems. The scanning electron microscope is also applicable for this type of analysis and has the added capability of identifying unknown agglomerates by energy dispersive x-ray analysis. Automated image-analysis techniques may also be utilized in conjunction with microscopical methods for quantifying the agglomeration of most types of pigments. For carbon blacks, the most suitable materials for on-line image analyses with transmitted light are plastics, paints, and inks which contain low black loadings. Higher carbon-black loadings in rubber can be analyzed by incident light using metallographic polishing of sulfur-hardened specimens. The microdispersion of carbon blacks at the primary aggregate level can be measured by means of electrical conductivity. This method is not applicable to inorganic pigments, large-particle-size carbon blacks, or blacks at very high or low loadings. Pigment microdispersion in different vehicle systems may also be assessed by means of scanning electron microscopy of thick cross sections (plasma etched to enhance contrast) or by transmission electron microscopy of thin cryosections. The tendency for the finer pigments to form 3-dimensional network structures in elastomers may also be measured as a function of the augmentation of dynamic modulus from high to low strain amplitudes. Pigment phase distribution in elastomer blends may be studied by scanning electron microscopy or transmission electron microscopy of thin cryosections, in conjunction with a staining or etching procedure to produce contrast between the separate polymer components. Selective staining is applicable to blends of polymers which differ significantly in their relative levels of unsaturation (e.g., NR/CIIR). Pyrolytic etching (under vacuum) may be used to produce interzone contrast in blends of polymers which differ significantly in their resistance to thermal degradation (e.g., NR/BR, NR/SBR). Pyrolysis GC may be utilized to determine the amount of carbon black in the separate phases of certain elastomer blends. This method is based on the relative intensity of the primary GC peaks for the individual polymers. The chromatographs are obtained from the bound rubber (carbon-polymer gel) that is developed during the mixing of the compound.

Carbon-Black-Elastomer Interaction

1991 ◽  
Vol 64 (1) ◽  
pp. 19-39 ◽  
Author(s):  
J. A. Ayala ◽  
W. M. Hess ◽  
F. D. Kistler ◽  
G. A. Joyce
Keyword(s):  
Carbon Black ◽  
Surface Activity ◽  
Chemical Reactivity ◽  
Surface Reactivity ◽  
Moisture Adsorption ◽  
Carbon Blacks ◽  
Bound Rubber ◽  
Carbon Black Surface ◽  
Black Surface ◽  
Polymer Interaction

Abstract A number of different techniques were applied to measure carbon-black-surface reactivity and the level of black-polymer interaction in four different elastomer systems (SBR, IIR, NR, and NBR) representing differences in unsaturation, crystallinity and polarity. Known within-grade surface activity variations were based on partial graphitization of an N121-type carbon black. The surface activity of different black grades was studied as a function of variations in both surface area and DBPA. Direct measurements of carbon-black-surface reactivity were based on hydrogen analysis, SIMS, IGC, and moisture adsorption. In-rubber measurements included bound rubber, SIMS of cut surfaces, and an interaction parameter, σ/η, which is derived from the slope (σ) of the stress-strain curve at low elongations, and (η), the ratio of dynamic modulus (E′) at 1% and 25% DSA. The following trends were observed: 1. The σ/η values provided a good measure of black-polymer interaction in all four polymer systems for either the within-grade or across-grade comparisons. 2. Higher σ/η values were indicated for SBR and NBR, followed by NR and IIR in that order. 3. SBR indicated the greatest sensitivity for bound-rubber measurements in terms of distinguishing within-grade variations in black-polymer interaction, followed by IIR, NR, and NBR in that order. 4. Positive SIMS on dry carbon black indicates the presence of complex hydrocarbon structures suitable for chemical reactivity at the carbon-black surface. 5. SIMS analyses on the dry carbon blacks exhibited intensity variations in the negative hydrocarbon fragments which were in line with the within-grade variations in hydrogen content. 6. SIMS analyses on the cut-rubber compound surfaces showed overall variations in intensity which were proportional to the range and level of the bound-rubber measurements. The most meaningful variations were recorded for SBR and IIR. 7. Heats of adsorption derived from IGC measurements with different adsorbates showed an excellent correlation with black-polymer interaction for the within-grade studies. Measurements across grades did not correlate as well with the in-rubber measurements, but the best results were obtained using styrene as the adsorbate. 8. The within-grade moisture adsorption measurements showed excellent agreement with IGC and the other techniques for the N121 series of heat-treated carbon blacks.

Effect of Temperature on the Transformation of Carbon Black into Nanotubes

2014 ◽  
Vol 875-877 ◽  
pp. 1565-1571 ◽  
Author(s):  
Vijayshankar Asokan ◽  
Dorte Madsen ◽  
Dhayalan Velauthapillai ◽  
Velaug Myrseth ◽  
Pawel Kosinski
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Black ◽  
Structural Transformation ◽  
Horizontal Tube ◽  
Synthesis Temperature ◽  
Degree Of Crystallinity ◽  
Effect Of Temperature ◽  
Metal Catalyst ◽  
Transmission Electron

In this paper, successful structural transformation of carbon black (CB) into nanotubes and nanoonion like structures at relatively low temperatures in the presence of transition metal catalyst is reported. This study focuses also on the influence of the temperature on the structural transformation of CB into nanostructures. The experiments were carried out at 700°C and 1000°C in a horizontal tube furnace under N2 atmosphere. The obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It was found that increase in the synthesis temperature from 700°C to 1000°C influences the morphology of the produced nanotubes significantly and the degree of crystallinity also increased with the temperature..

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