Autoradiographic Technique with Carbon14 in Rubber

1952 ◽  
Vol 25 (2) ◽  
pp. 291-302
Author(s):  
A. D. Kirshenbaum ◽  
C. W. Hoffman ◽  
A. V. Grosse
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Strength Data ◽  
Autoradiographic Technique ◽  
Carbon Black Dispersion

Abstract The autoradiograph technique making use of carbon14 is useful in studying the carbon black distribution in rubber. It is superior to the photomicrographic technique in studying carbon black dispersion in rubber. Autoradiographs of different carbon black-rubber mixes (tensile strengths varying from 300 to 3300 pounds per square inch) showed visible variations in the carbon black distribution which closely agree with the tensile strength data, whereas photomicrographs of the same mixes showed no differences among the various mixes. The autoradiographic technique is also useful in tracking down carbon black agglomeration in rubber.

Solution Masterbatching Studies

1966 ◽  
Vol 39 (3) ◽  
pp. 553-566 ◽  
Author(s):  
C. E. Scott ◽  
F. J. Eckert
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Dynamic Modulus ◽  
Polymer Adhesion ◽  
Electron Microscope Analysis ◽  
Carbon Gel ◽  
Conventional Manner ◽  
Mixed Stock ◽  
Carbon Black Dispersion ◽  
Better Than

Abstract Hydrosolution masterbatching (HSMB) imparts excellent dispersion and improved pigment-to-polymer adhesion to carbon and oil masterbatches of poly-butadiene, SBR and blends of these rubbers. Tire tests show HSMB stocks to resist wear slightly better than like stocks mixed in a conventional manner. The HSMB process can be used to produce fully compounded vulcanizable tread stocks in which the stock is discharged continuously from a drying extruder. The dispersion and adhesion advantages of HSMB stocks are also noted in complete masterbatches. HSMB oil, black, and polymer masterbatches usually have higher viscosity, tensile strength, hardness, and dynamic modulus but lower resilience and reduced scorch safety, in comparison with conventionally mixed stock. Carbon black dispersion as revealed by light and electron microscope analysis is excellent. Experiments characterizing carbon gel and development of carbon black dispersion on HSMB stocks (vacuum dried), indicate the total effective molecular contact between elastomer and pigment to be increased, so that, in effect, surface area is increased.

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.

The Influence of Interstitial Liquids on the Cohesive Strength of Carbon-Black Agglomerates

1989 ◽  
Vol 62 (5) ◽  
pp. 928-938 ◽  
Author(s):  
Steven W. Horwatt ◽  
Syang-Peng Rwei ◽  
Ica Manas-Zloczower ◽  
Donald L. Feke
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Cohesive Strength ◽  
Liquid Content ◽  
Strength Data ◽  
Order Of Magnitude ◽  
Hamaker Constants

Abstract The influence of interstitial liquids on the cohesive strength of carbon black has been investigated. Calculations of effective Hamaker coefficients for the wet materials predicted order of magnitude decreases from the Hamaker constants for the dry materials. Tensile-strength data showed slight increases over the Hamaker constants for the dry materials. It is clear that further research is needed to elucidate the effects of liquid content and wettability.

States of Carbon Black Dispersion and Extensibility of Rubbers

1993 ◽  
Vol 66 (2) ◽  
pp. 317-328 ◽  
Author(s):  
Asahiro Ahagon
Keyword(s):  
Carbon Black ◽  
Tensile Property ◽  
Crosslink Density ◽  
Hydrodynamic Effect ◽  
Property Variation ◽  
Agglomerate Size ◽  
Filled Rubber ◽  
Two Temperatures ◽  
Confined Polymer ◽  
Carbon Black Dispersion

Abstract Analysis is made for the origin of the mixing-induced tensile property variation of a filled rubber. Attention is paid to the hydrodynamic effect f(ϕe) of the filler, defined here as the factor to adjust the deviation of 100% modulus from the theory of rubber elasticity. For the rubbers mixed under variety of conditions, the f(ϕe)'s are calculated from the observed values of the modulus, at 25°C and 100°C, and the crosslink density. The variation of the f(ϕe) is considered to be governed by the mobility of the polymer confined in agglomerates of the filler. The mobility variation due to mixing seems to be mainly influenced by agglomerate size at 25°C, and by agglomerate size and chemical constraints at 100°C. Therefore, the f(ϕe)'s at the two temperatures are suggested to be useful measures of the state of carbon-black micro-dispersion. The extensibility of the rubbers is closely related f(ϕe). This indicates that the failure property is also governed by the mobility of the confined polymer.

Effect of Diameter and Surface Area of Carbon Black Particles on Certain Properties of Rubber Compounds

1944 ◽  
Vol 17 (2) ◽  
pp. 451-474
Author(s):  
D. Parkinson
Keyword(s):  
Particle Size ◽  
Tensile Strength ◽  
Carbon Black ◽  
Abrasion Resistance ◽  
Particle Diameter ◽  
Stiffness Modulus ◽  
Carbon Structures ◽  
Rubber Compounds ◽  
Regular Manner ◽  
Tear Resistance

Abstract Carbon blacks can be grouped into different classes according to the way in which their fineness of division relates to different properties in rubber. Within any one class the principal properties vary in a regular manner with particle size. The normal class consists of the furnace carbons, Kosmos (Dixie)-40, Statex, the rubber-grade impingement carbons, and possibly, the color-grade impingement carbons. The subnormal classes consist of thermal carbons and acetylene and lamp blacks. Irrespective of the above classification, the properties which depend more on fineness of division than on other factors are rebound resilience, abrasion resistance, tensile strength and tear resistance. The lower limit of particle diameter for best tensile strength and tear resistance appears to be higher than that for abrasion resistance. B.S.I, hardness and electrical conductivity are properties which depend at least as much on other factors as on particle size. Stiffness (modulus) depends more on other factors than on particle size. Factors modifying the effects of particle size (or specific surface) include the presence of carbon-carbon structures and a reduction in strength of bond in rubber-carbon structures. Carbon black is thought to exist in rubber in four states: agglomerated, flocculated, dispersed, and bonded to the rubber molecules (the reënforcing fraction). Abrasion resistance is regarded as providing the only reliable measure of reënforcement.

Sign in / Sign up

Export Citation Format

Share Document