scholarly journals THIXOTROPIC FLOCCULATION EFFECTS IN CARBON BLACK–REINFORCED RUBBER: KINETICS AND THERMAL ACTIVATION

2021 ◽  
Author(s):  
Lewis B. Tunnicliffe
Keyword(s):  
Carbon Black ◽  
Surface Area ◽  
Thermal Activation ◽  
Spherical Particles ◽  
Carbon Blacks ◽  
Creep Flow ◽  
Wide Range ◽  
Activation Data ◽  
Aggregate Morphology ◽  
Future Work

ABSTRACT A new rheological methodology is used to quantify the kinetics and thermal activation of thixotropic recovery (flocculation) of uncrosslinked carbon black–reinforced emulsion SBR following high shears and over a range of annealing temperatures. A wide range of carbon black types are examined to determine the influence of aggregate morphology and surface area on compound flocculation. Several kinetic parameters are correlated with the carbon black aggregate structure and surface area, the results of which imply a transition in mechanisms controlling modulus recovery between shorter and longer recovery time scales. Thermal activation of flocculation is found to scale to the surface area and to the mean aggregate diameter of the carbon blacks following power law relationships. The thermal activation data for a subset of compounds with different carbon blacks prepared at different loadings collapses onto a single master line by rescaling the data to a parameter that is proportional to the theoretical interparticle force calculated for the idealized situation of two spherical particles in proximity. Three different van der Waals force models are evaluated, and in each case, an effective superposition of the thermal activation data is achieved. This indicates that the attractive force between aggregates plays a key role in the flocculation of carbon black in rubber, and this force can be traced back to the aggregate and primary particle sizes, interaggregate distances, and effective volume fractions. The activation energy for the viscosity of the unfilled, uncrosslinked SBR is similar to analogous values calculated for the thermal activation of flocculation. This coupling of energetics may be the result of creep/flow of rubber out of gaps between aggregates resulting from interaggregate attractive forces and any potential diffusive motion of the aggregates. Bound rubber data appear to contain information relating to aggregate packing, which could be exploited in future work to further explore the mechanism of flocculation.

Another Look at S-Type Carbon Blacks

1977 ◽  
Vol 50 (1) ◽  
pp. 211-216
Author(s):  
J. R. Haws ◽  
W. T. Cooper ◽  
E. F. Ross
Keyword(s):  
Carbon Black ◽  
Surface Area ◽  
Good Adhesion ◽  
Good Resistance ◽  
Carbon Blacks ◽  
Rubber Compounds ◽  
Curing Characteristics ◽  
Wide Range ◽  
Oxidized Carbon

Abstract Oxidized carbon blacks impart unique properties to rubber compounds. The most interesting aspects include modified curing characteristics, good resistance to tear, and the potential to promote good adhesion of rubber compounds to brass-plated metal. When these improvements are considered in conjunction with the wide range of surface area and structure available in carbon black, it is evident that oxidized furnace blacks provide combinations of properties not previously available.

The Influence of Carbon Black, Mixing, and Compounding Variables on Dispersion

1984 ◽  
Vol 57 (5) ◽  
pp. 959-1000 ◽  
Author(s):  
W. M. Hess ◽  
R. A. Swor ◽  
E. J. Micek
Keyword(s):  
Shear Stress ◽  
Carbon Black ◽  
Shear Strain ◽  
Surface Area ◽  
Mixing Time ◽  
Strength Properties ◽  
High Dispersion ◽  
Carbon Blacks ◽  
Wide Range ◽  
Black Oil

Abstract A series of response equations relating dispersion and rubber properties to mixing and compounding variables have been developed for formulations based on SBR and EPDM. These provide insight on the relationship of dispersion to rubber performance as carbon black type and loading are widely varied. Optimum conditions have been defined for minimizing Banbury mixing time and power consumption to achieve acceptable dispersion for different grades of carbon black. The different blacks can be classified in terms of their relative tendency to be shear-stress or shear-strain sensitive. The finer, low-DBPA carbon blacks such as N326 are shear-stress sensitive. To achieve high dispersion levels, this type of black requires initially high compound viscosities, i.e., by means of high loadings, withholding all or part of the extender oil until after black incorporation, or by high black/oil ratios. The coarser, high-DBPA carbon blacks such as N650 are more shear-strain dependent and will reach high dispersion levels if enough energy (usually relatively low) is imparted to the batch during Banbury mixing. N650 consistently gave high dispersion levels over a wide range of black/oil levels, regardless of the polymer type or mixing variables. Carbon black dispersibility in SBR-1500 was improved in the direction of increasing DBPA and decreasing surface area. The surface area response was most pronounced when loose oil was added with the black. High oil with the carbon black tends to form harder, more persistent agglomerates which have a greater depressing effect on rubber strength properties such as tensile and fatigue. The effect of carbon black surface area on dispersion was considerably less in SBR-1712 with no loose oil addition. In EPDM, upside-down mixes of different grades of black at varied black/oil loadings produced some notable changes in the dispersion response to carbon black DBPA. At some of the high black/oil ratios, low DBPA was actually beneficial to dispersion. The finer, higher-DBPA blacks such as N351 showed a tendency to form more persistent agglomerates analogous to conventional SBR-1500 mixes in which high amounts of loose oil are added with low-DBPA blacks. These persistent agglomerates are most prone to form in an EPDM upside-down mix when the oil loading is close to the absorptive capacity of the carbon black. The Banbury power profiles of such compounds indicated a high initial peak and a depressed or missing second peak. A normal power profile and a high level of dispersion were achieved with these problem mixes when 25 to 50% of the oil was withheld until after black incorporation. N650 gave excellent dispersion in EPDM at all black/oil loadings and only minimal variations in vulcanizate properties were observed at mixing times ranging from 1 to 5 min.

PERMEABILITY STUDIES: III. SURFACE AREA MEASUREMENTS OF CARBON BLACKS

1948 ◽  
Vol 26a (2) ◽  
pp. 29-38 ◽  
Author(s):  
J. C. Arnell ◽  
G. O. Henneberry
Keyword(s):  
Electron Microscope ◽  
Low Temperature ◽  
Carbon Black ◽  
Surface Area ◽  
Satisfactory Agreement ◽  
Nitrogen Adsorption ◽  
Average Particle ◽  
Carbon Blacks ◽  
Permeability Studies ◽  
Nitrogen Adsorption Isotherms

The modified Kozeny equation has been found to be satisfactory for the measurement of the specific surfaces of carbon blacks having average particle diameters ranging from 0.01 to 0.1 μ to within ±10%. Comparative data were obtained from electron microscope counting and from low temperature nitrogen adsorption isotherms. The three methods examined gave results that were in satisfactory agreement, except when the carbon black was porous, and then the adsorption value was extremely large.

THE ADSORPTION OF SODIUM MYRISTATE BY CARBON BLACK

1949 ◽  
Vol 27f (11) ◽  
pp. 426-428 ◽  
Author(s):  
Marguerite A. Reade ◽  
A. S. Weatherburn ◽  
C. H. Bayley
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Fatty Acid ◽  
Carbon Black ◽  
Surface Area ◽  
Activated Charcoal ◽  
Carbon Blacks ◽  
Preferential Adsorption

The adsorption of sodium myristate from 0.1% aqueous solution by a series of carbon blacks and an activated charcoal has been measured at 70 °C. In every case a preferential adsorption of fatty acid was observed. The extent of adsorption of both the fatty acid and alkali components of the soap increased with decreasing particle size, i.e., with increasing surface area, of the carbons. The adsorption by activated charcoal was considerably higher than that obtained with even the finest of the carbon blacks.

Properties of CB/Rubber Composites Filled by Carbon Black Used as Catalysts for Hydrocarbon Decomposition

2007 ◽  
Vol 26-28 ◽  
pp. 301-304
Author(s):  
Shuang Ye Dai ◽  
Ge You Ao ◽  
Myung Soo Kim
Keyword(s):  
Tensile Strength ◽  
Weight Gain ◽  
Hydrogen Production ◽  
Carbon Black ◽  
Surface Area ◽  
Decomposition Reaction ◽  
Carbon Blacks ◽  
Carbon Deposits ◽  
Operation Conditions ◽  
Low Weight

Carbon blacks were used as catalysts for hydrogen production through hydrocarbon decomposition. The aim of this work is to find suitable conditions for decomposition reaction to cut down the net cost of hydrogen production. Carbon blacks after hydrocarbon decomposition under different operation conditions were mixed with NBR rubber. The surface area of carbon black increased with low weight gain in methane decomposition caused by carbon deposits on the surface of carbon black aggregates, and the decrease of surface area with further weight gain might be due to the carbon deposits adhering to each other and forming bigger aggregates. The same results were gotten from decomposition of mixture gas of methane and propane. The surface area of carbon black always decreased with the development of propane decomposition reaction. With the same carbon black loading, the composites filled by carbon blacks with low weight gain in methane and methane-propane mixture gas decompositions showed higher tensile strength than those mixed with raw carbon blacks, but there were no significant differences in 300% modulus. With the increase of carbon blacks loading in all composites, 300% modulus and tensile strength always increased. The surface resistivity of composites showed that it was much easier for carbon blacks with low weight gain in methane and methane-propane mixture gas decompositions to dissipate well in the in rubber system.

A Quantitative Study of the Carbon Black Reinforcement System for Tire Tread Compounds

1979 ◽  
Vol 52 (4) ◽  
pp. 748-763 ◽  
Author(s):  
A. G. Veith ◽  
V. E. Chirico
Keyword(s):  
Wear Resistance ◽  
Carbon Black ◽  
Surface Area ◽  
High Performance ◽  
Materials Science ◽  
Normal Structure ◽  
Wear Testing ◽  
Reinforcement System ◽  
Wear Rates ◽  
Carbon Blacks

Abstract This comprehensive program clearly shows the influence of the four defined reinforcement system variables. The tread wear testing conducted over an extremely wide severity range illustrates how the influence of each variable or factor changes as the tire use of test severity is changed. The quantitative influence of the four variables is best illustrated by the index severity gradient, while the index range serves as a quick indicator. The influence of each factor of the reinforcement system increases as general test severity is increased. Carbon blacks with high structure and surface area are substantially superior to blacks with normal structure and surface area at the higher test severities. At the higher general severities, increased oil content produces higher wear rates. At any given severity level, the rate of wear passes through a minimum as carbon black level is increased. The carbon black content at this minimum wear rate shifts to higher values as general severity is raised. Test results at a series of specific cornering force levels (0.10–0.30 g range) indicate that the relative wear of typical tread compounds demonstrates crossovers of index values. Compounds that show superior wear resistance compared to a reference compound at high cornering severities often show inferior wear resistance at low cornering severities. Therefore, for maximum tread life or wear resistance, the reinforcement system with any tread rubber or rubber blend must be carefully adjusted to the anticipated level of tire use severity. The introduction of improved-technology carbon blacks with increased rubber-black interaction that is promoted by high DBP and EMA levels is a substantial advancement in rubber materials science and is most important for the production of high-performance long-treadlife tires.

Carbon Black Surface Areas by the Harkins and Jura Absolute Method

1967 ◽  
Vol 40 (5) ◽  
pp. 1305-1310 ◽  
Author(s):  
G. Kraus ◽  
K. W. Rollmann
Keyword(s):  
Particle Size ◽  
Carbon Black ◽  
Surface Area ◽  
Nitrogen Adsorption ◽  
Absolute Method ◽  
Carbon Blacks ◽  
Surface Areas ◽  
Particle Size Determination ◽  
Light Reflectance ◽  
Adsorption Surface

Abstract The Harkins and Jura (HJ) absolute method of surface area determination (Harkins and Jura, J. Am. Chem. Soc. 66, 919, 1944) has been applied to a large number of carbon blacks. Surface area is calculated from the heat of immersion of the solid powder covered by a preadsorbed multilayer of the immersion liquid. For non-porous carbon blacks good agreement with nitrogen adsorption surface areas is obtained, but with porous blacks the HJ method gives smaller values since micropores are filled and bridged over by the pre-adsorbed film. Thus the HJ areas are more nearly representative of particle size and may be used to calibrate indirect methods of particle size determination. An example of this is shown using light reflectance values on dry carbon black and possible complications due to particle size distribution in the use of the reflectance test are discussed.

scholarly journals Nanostructure Quantification of Carbon Blacks

2018 ◽  
Vol 5 (1) ◽  
pp. 2 ◽  
Author(s):  
Madhu Singh ◽  
Randy Vander Wal
Keyword(s):  
Carbon Black ◽  
Material Properties ◽  
Nanometer Scale ◽  
Fringe Analysis ◽  
Combustion Condition ◽  
Carbon Blacks ◽  
Production Processes ◽  
Transmission Electron ◽  
Aggregate Morphology ◽  
End Use

Carbon blacks are an extensively used manufactured product. There exist different grades by which the carbon black is classified, based on its purpose and end use. Different properties inherent to the various carbon black types are a result of their production processes. Based on the combustion condition and fuel used, each process results in a carbon black separate from those obtained from other processes. These carbons differ in their aggregate morphology, particle size, and particle nanostructure. Nanostructure is key in determining the material’s behavior in bulk form. A variety of carbon blacks have been analyzed and quantified for their lattice parameters and structure at the nanometer scale, using transmission electron microscopy and custom-developed fringe analysis algorithms, to illustrate differences in nanostructure and their potential relation to observed material properties.

scholarly journals A Case Study of Waste Scrap Tyre-Derived Carbon Black Tested for Nitrogen, Carbon Dioxide, and Cyclohexane Adsorption

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4445 ◽  
Author(s):  
Zuzana Jankovská ◽  
Marek Večeř ◽  
Ivan Koutník ◽  
Lenka Matějová
Keyword(s):  
Activated Carbon ◽  
Carbon Black ◽  
Specific Surface ◽  
Surface Area ◽  
Sorption Capacity ◽  
Specific Surface Area ◽  
Textural Properties ◽  
Pyrolytic Carbon ◽  
Surface Areas ◽  
Wide Range

Waste scrap tyres were thermally decomposed at the temperature of 600 °C and heating rate of 10 °C·min−1. Decomposition was followed by the TG analysis. The resulting pyrolytic carbon black was chemically activated by a KOH solution at 800 °C. Activated and non-activated carbon black were investigated using high pressure thermogravimetry, where adsorption isotherms of N2, CO2, and cyclohexane were determined. Isotherms were determined over a wide range of pressure, 0.03–4.5 MPa for N2 and 0.03–2 MPa for CO2. In non-activated carbon black, for the same pressure and temperature, a five times greater gas uptake of CO2 than N2 was determined. Contrary to non-activated carbon black, activated carbon black showed improved textural properties with a well-developed irregular mesoporous-macroporous structure with a significant amount of micropores. The sorption capacity of pyrolytic carbon black was also increased by activation. The uptake of CO2 was three times and for cyclohexane ten times higher in activated carbon black than in the non-activated one. Specific surface areas evaluated from linearized forms of Langmuir isotherm and the BET isotherm revealed that for both methods, the values are comparable for non-activated carbon black measured by CO2 and for activated carbon black measured by cyclohexane. It was found out that the N2 sorption capacity of carbon black depends only on its specific surface area size, contrary to CO2 sorption capacity, which is affected by both the size of specific surface area and the nature of carbon black.

Filler Aggregates and Their Effect on Reinforcement

1974 ◽  
Vol 47 (2) ◽  
pp. 411-433 ◽  
Author(s):  
A. I. Medalia
Keyword(s):  
Carbon Black ◽  
Fine Particles ◽  
High Surface ◽  
High Surface Area ◽  
Experimental Studies ◽  
Spherical Particles ◽  
Rubber Compound ◽  
Carbon Blacks ◽  
Reinforcing Fillers ◽  
Aggregate Nature

Abstract The most highly reinforcing fillers, namely carbon blacks and silicas, consist of aggregates of quasi-spherical particles fused together. In the absence of direct experimental studies with single-particle carbon blacks or silicas of high surface area, we cannot be sure if aggregated structure is essential for good reinforcement, or whether aggregation and fusion just happen to accompany the formation of fine particles at practical concentrations. In any case, there is no doubt that the aggregate nature of the filler plays a major role in determining the properties of the rubber compound. Here I would like to review what we know about filler aggregates, especially of carbon black, and suggest some mechanisms for their effects on rubber; and also indicate where our knowledge seems inadequate at the present time.

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