Carbon Black Dispersion Measurement in Rubber Vulcanizates via Interferometric Microscopy

2004 ◽  
Vol 77 (4) ◽  
pp. 691-710 ◽  
Author(s):  
Archie P. Smith ◽  
Toni L. Aybar ◽  
Ricky W. Magee ◽  
Charles R. Herd
Keyword(s):  
Carbon Black ◽  
Three Dimensional ◽  
Dispersion Index ◽  
Complete Understanding ◽  
Additional Information ◽  
Rubber Compounds ◽  
Varying Dispersion ◽  
Light Beams ◽  
Cut Surface ◽  
Carbon Black Dispersion

Abstract A new method for characterizing the carbon black dispersion in rubber compounds is introduced. This technique is based on interferometric microscopy (IFM) and utilizes the interference fringes between in-phase light beams reflected from the rubber sample and a smooth reference surface to measure the three-dimensional surface topography. The peaks and valleys present on the fresh-cut surface are representative of the carbon black agglomerates and are used to characterize the dispersion. A series of samples with different base rubbers and varying dispersion levels were created and characterized by both light microscopy and IFM. These results were used to generate a universal dispersion index based on the IFM data that correlates well with the LM dispersion index values. In addition, three-dimensional peak statistics were obtained from the IFM data and used to provide additional information about the carbon black agglomerate distribution. This data can be used for a more complete understanding of the compound behavior as a function of the carbon black dispersion and agglomerate distribution.

Some Initial Trials and Applications of the DFCS Test for Carbon Black Dispersion

1997 ◽  
Vol 70 (1) ◽  
pp. 38-49
Author(s):  
G. A. W. Murray ◽  
B. H. R. Ng ◽  
M. R. Vaseghi Jahromi ◽  
D. W. Southwart
Keyword(s):  
Standard Deviation ◽  
Carbon Black ◽  
Normal Distribution ◽  
Quantitative Method ◽  
Scattered Light ◽  
Dark Field ◽  
Test Results ◽  
Rubber Compounds ◽  
Cut Surface ◽  
Carbon Black Dispersion

Abstract The Dark Field Cut Surface (DFCS) test is a quantitative method for determining the state of dispersion of carbon black in rubber compounds. The method has been described fully in another paper. Here are reported some of the first applications of the test and some trials that were carried out specifically to investigate and develop the DFCS test. The test is demonstrated to follow accurately the progress of dispersion of carbon black in milled or mixed compounds of NR and SBR. Some tests have been carried out using large batches of test results and these have demonstrated a good fit with a normal distribution. By this means, some recommendations have been derived for suitable sampling rates. The relative merits of the standard deviation and the average for characterizing dispersion have been highlighted. A further way of presenting the results as distribution curves has been demonstrated. A check has been performed to demonstrate that mastication of rubber has little or no influence on the DFCS test results. The DFCS test has been used to give an interesting (provisional) insight to the best ways to operate a rubber mixer. To date, the measured patterns of scattered light show a promising correlation with the anticipated dispersion of carbon black in the specimens tested.

Oxidation of Unvulcanized Cold Rubber Influence of Adsorption by Carbon Black

1952 ◽  
Vol 25 (3) ◽  
pp. 557-572
Author(s):  
C. W. Sweitzer ◽  
Francis Lyon
Keyword(s):  
Carbon Black ◽  
Surface Chemistry ◽  
Carbon Films ◽  
Cross Linking ◽  
Additional Information ◽  
Rubber Compounds ◽  
Repressive Effect ◽  
Solvent Systems ◽  
Dilute System

Abstract Previous investigations have shown a large difference between the amount of rubber insolubilized by carbon black in dilute solvent systems and in standard mill mixes. The purpose of this study, after reconciling these extremes, was to evaluate the role of adsorption in the insolubilization of rubber in mill-mixed compounds. An adsorption test was employed which eliminated the solvent effect of the dilute system and the mastication effect in mill mixing. Results showed that carbon black, depending on the temperature and atmosphere conditions imposed on the rubber carbon films, represses the scission, cross-linking, and gelation reactions of GR-S X-478. This repressive effect is ascribed to the adsorption and inactivation by the carbon black of the oxidized intermediates through which these various reactions proceed. The magnitude of this effect was found to vary with the type, loading, and surface chemistry of the carbon. This approach not only offers promise as a means for predicting the behavior of carbon black in rubber compounds, but also, because of its applicability to the study of all rubber-carbon systems, offers possibilities of providing additional information on the mechanism of the carbon-rubber bond.

The Dark Field Cut Surface (DFCS) Test for Estimating the Dispersion of Carbon Black in Rubber Compounds

1997 ◽  
Vol 70 (1) ◽  
pp. 50-59 ◽  
Author(s):  
G. A. W. Murray ◽  
D. W. Southwart ◽  
P. K. Freakley
Keyword(s):  
Carbon Black ◽  
Numerical Estimate ◽  
Dark Field ◽  
Field Of View ◽  
High Magnification ◽  
Ability To Work ◽  
Rubber Compounds ◽  
Dark Field Illumination ◽  
Cut Surface ◽  
Initial Results

Abstract A test for estimating the dispersion of carbon black in rubber compounds is described. It works by examining the freshly cut surface of a specimen at low magnification in dark field illumination. Roughness of the surface related to the presence of carbon black causes increased reflection under dark field illumination. The illumination of each field of view is examined as 100 subdivisions and the relative values of these readings give a numerical estimate of the dispersion. Details of how this is done and the corrections applied to the results are described. A second paper reports some initial results obtained with the test. The test works well for certain elastomers, notably NR and SBR. The biggest advantage of the test is its ability to work rapidly and cheaply on small zones at relatively high magnification. This opens up the possibility of detailed studies of macroscopic variations in dispersion, done in reasonable times and at reasonable costs.

Effect of Processing Additives on Carbon Black Dispersion and Grip Property of High-Performance Tire Tread Compound

1997 ◽  
Vol 70 (1) ◽  
pp. 15-24 ◽  
Author(s):  
H. Takino ◽  
S. Iwama ◽  
Y. Yamada ◽  
S. Kohjiya
Keyword(s):  
Carbon Black ◽  
Viscoelastic Properties ◽  
High Performance ◽  
Mixing Process ◽  
Remarkable Effect ◽  
Rubber Compounds ◽  
Carbon Black Surface ◽  
Black Surface ◽  
Power Curves ◽  
Carbon Black Dispersion

Abstract Rubber and carbon black compounds show complex behaviors in their mixing process due to their complicated microcomposite structure. Therefore, establishing a clear relationship between the mixing state of the rubber compound and the physical properties of its cured rubber has still remained to be solved in spite of formidable efforts by many rubber technologists. This paper investigated the influence of a processing additive on the carbon black incorporation and its dispersion behavior by inspecting Banbury power curves. From this investigation, we considered that good wettability toward the carbon black surface was necessary for processing additives in order to improve carbon black dispersion. The function of the processing additive was thought to enhance the surface lubrication of carbon black for disagglomeration in the early steps of mixing. The dry grip properties of a tire was estimated from the temperature dependence of dynamic viscoelastic properties of rubber compounds, with improved carbon black dispersion due to the processing additive; and it was confirmed by an actual tire running evaluation. Consequently, we found that tread compounds with improved carbon black dispersion had a remarkable effect on tire dry-grip properties at high temperatures.

Measurement of Carbon Black Dispersion in Rubber by Surface Analysis

1978 ◽  
Vol 51 (4) ◽  
pp. 817-839 ◽  
Author(s):  
P. C. Vegvari ◽  
W. M. Hess ◽  
V. E. Chirico
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Carbon Black ◽  
Distinct Advantage ◽  
Dispersion Index ◽  
Programmable Calculator ◽  
Wide Range ◽  
Heat Buildup ◽  
Carbon Black Dispersion

Abstract A stylus-type surface roughness tester has been applied to the study of carbon black dispersion in a number of different rubber systems. The method is based on a freshly cut rubber surface which is tracked by the stylus to provide a roughness trace on a strip chart. Carbon black agglomerates deflect the cut path because of their higher hardness relative to the surrounding matrix. Thus, surface roughness diminishes at increasing levels of dispersion. A quantitative index of dispersion quality may be derived from the frequency and average height of the roughness peaks. The method offers a distinct advantage over previous methods in its ability to provide precise dispersion ratings over a very wide range of rubber processing levels from the masterbatch to the final product. The technique is applicable to the analysis of unvulcanized rubber compounds and could be utilized as a factory quality control procedure. Direct interfacing of the surface analyzer to a programmable calculator would provide quantitative dispersion ratings within five minutes of the receipt of a sample. Studies of varied carbon black dispersions in SBR and SBR/BR passenger tread formulations have confirmed the work of previous authors. Tensile strength, fatigue life, resilience, elongation, and extrusion shrinkage increased at higher dispersion levels, while Mooney viscosity, Shore hardness and heat buildup exhibited a progressive decrease. The properties of a 50/50 NR/BR truck tread formulation showed a more varied response to black dispersion. Tensile strength and resilience showed considerably less dispersion dependence than SBR and SBR/BR. However, the tensile response increases with increasing black fineness and decreasing structure, while resilience showed the opposite trend. Fatigue life and heat buildup showed the same trends observed for SBR and SBR/BR. However, NR/BR treadwear (radial tires) showed considerably less dependence on dispersion above the 70% level, in comparison to those other polymers (bias ply tires). NR/BR with N220 at a dispersion index of 68 gave treadwear resistance that was equivalent to the same compound at a dispersion index of 89. However, dispersion indices of 50 or lower caused severely depressed treadwear resistance for the different blacks that were tested. The milling of NR/BR masterbatches cooled overnight produced significantly higher dispersion levels in comparison to hot batches at the same total mixing energy. This procedure can be employed to optimize treadwear and other properties at lower levels of energy consumption.

Online Characterization of the Effect of Mixing Parameters on Carbon Black Dispersion in Rubber Compounds Using Electrical Conductivity

2004 ◽  
Vol 77 (1) ◽  
pp. 147-160 ◽  
Author(s):  
H. H. Le ◽  
S. Ilisch ◽  
B. Jakob ◽  
H.-J. Radusch
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Mixing Parameters ◽  
Rubber Compounds ◽  
Mixing Regime ◽  
Internal Mixer ◽  
Optimal Mixing ◽  
Insight Into ◽  
Carbon Black Dispersion

Abstract The influences of mixing parameters on the carbon black dispersion can be characterized using the electrical conductivity online measured from internal mixer. As a measure for monitoring the development of carbon black dispersion, a normalized conductivity with regard to the conductivity measured at the BIT (black incorporation time) has been suggested. It is observed that in spite of different mixing parameters, the mixtures possessing the same normalized conductivity factor K/KBIT deliver the same carbon black dispersion and the same mechanical properties. Based on normalized conductivity, a deeper insight into the mixing kinetics can be provided to find an optimal mixing regime.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

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