Limiting Law of the Reinforcement of Rubber

1945 ◽  
Vol 18 (2) ◽  
pp. 292-305 ◽  
Author(s):  
Hugh M. Smallwood
Keyword(s):  
Molecular Structure ◽  
Experimental Data ◽  
Particle Size ◽  
Zinc Oxide ◽  
Carbon Black ◽  
Filler Particle ◽  
Rubber Matrix ◽  
Volume Loading ◽  
Volume Percentage ◽  
Filler Particles

Abstract 1. Analysis shows that, subject to certain limitations, the modulus of a loaded stock (M*) depends on the modulus of the rubber matrix (M), according to the equation: M*=M(1+2.5ϕ) where 100ϕ is the volume percentage of filler. When these limitations are fulfilled, the effect of compounding on modulus is, therefore, independent of the particle size of the filler. The assumptions on which this equation is founded are as follows: (1) the filler particles are spherical; (2) there is complete adhesion between rubber and filler; (3) the elongation is small; (4) the filler is completely dispersed; (5) the volume loading is small; (6) the filler particles are sufficiently large that the molecular structure of the rubber may be neglected. 2. The stresses about a filler particle have been derived mathematically. 3. Experimental data check the calculations for the following fillers: P-33, Thermax, and whiting. Catalpo clay presents some anomalies because of its acicular particles. 4. Carbon black does not conform to the calculations. This is attributed to the fact that it is strongly flocculated in rubber. 5. Zinc oxide (Kadox or XX zinc oxide), which should conform, because it is well dispersed in rubber, causes abnormally large increases in modulus, presumably because of alteration of the type of cure and consequent alteration of the modulus of the rubber matrix.

Numerical Simulation for Mechanical Behavior of Carbon Black Filler Particle Reinforced Rubber Matrix Composites

2011 ◽  
Vol 137 ◽  
pp. 1-6
Author(s):  
Qing Li ◽  
Xiao Xiang Yang
Keyword(s):  
Carbon Black ◽  
Mechanical Behavior ◽  
Plane Stress ◽  
Volume Fraction ◽  
Filler Particle ◽  
Three Dimensional ◽  
Rubber Matrix ◽  
Two Dimensional ◽  
Rubber Composites ◽  
Dimensional Plane

In this paper, the micromechanical finite element method based on Representative Volume Element has been applied to study and analyze the macro mechanical properties of the carbon black filled rubber composites by using two-dimensional plane stress simulations and three-dimensional axisymmetric simulations under uniaxial compression respectively. The dependence of the macroscopic stress-strain behavior and the effective elastic modulus of the composites, on particle shape, particle area/volume fraction and particle stiffness has been investigated and discussed. Additionally, the simulation results of the two-dimensional plane stress model and the three-dimensional axisymmetric model are evaluated and compared with the experimental data, which shows that the two-dimensional plane stress simulations generate poor predictions on the mechanical behavior of the carbon black particle reinforced rubber composites, while the three-dimensional axisymmetric simulations appear to give a better prediction.

Deformation of Filler Morphology in Strained Carbon Black Loaded Rubbers. A Study by Atomic Force Microscopy

1995 ◽  
Vol 68 (4) ◽  
pp. 652-659 ◽  
Author(s):  
S. Maas ◽  
W. Gronski
Keyword(s):  
Atomic Force Microscopy ◽  
Carbon Black ◽  
Average Distance ◽  
Rubber Matrix ◽  
Large Strains ◽  
Direction Parallel ◽  
Force Microscopy ◽  
Atomic Force ◽  
Affine Deformation ◽  
Filler Particles

Abstract The changes of the filler morphology of SBR vulcanizates loaded with 10 phr carbon black (N234 and N990) subjected to large strains were studied by Atomic Force Microscopy and image analysis. It was found that the filler particles tend to align in the force field. The average distance of the filler particles at the surface in the direction parallel and perpendicular to the strain direction is much smaller then according to affine deformation. The measurements give evidence of the inhomogeneous deformation of the rubber matrix and demonstrate the onset of failure at large deformation.

Rheological Behavior of Highly Filled EPDM Compounds with Calcium Carbonate, Carbon Black, Silica and Zinc Oxide

1996 ◽  
Vol 69 (4) ◽  
pp. 628-636 ◽  
Author(s):  
Li Li Li ◽  
James L. White
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Calcium Carbonate ◽  
Shear Rate ◽  
Carbon Black ◽  
Shear Viscosity ◽  
Volume Fraction ◽  
Carbonate Carbon ◽  
Yield Value ◽  
Yield Values

Abstract The shear viscosity, creep and constant shear rate transients have been measured for 0.20 volume fraction compounds of an EPDM with calcium carbonate, carbon black, silica and zinc oxide of similar particle size at 100°C. Measurements have been made in a creep sandwich instrument, pressurized rotational rheometer and a capillary rheometer and cover nine decades of shear rate. All of the compounds exhibit enhanced viscosities and yield values; i.e. there are stresses below which there is no flow. The greatest yield values and increased viscosities are with the compounds with calcium carbonate and zinc oxide. More extensive studies were made with the EPDM-calcium carbonate system, where it was shown that, increasing particle size reduces shear viscosity and yield values. Further, surface treating calcium carbonate with stearic acid signifcantly reduces the shear viscosity and yield value of the corresponding EPDM compound.

Some Effects of Solid Fillers in Rubbers

1953 ◽  
Vol 26 (1) ◽  
pp. 156-165
Author(s):  
Ira Williams
Keyword(s):  
Tensile Strength ◽  
Zinc Oxide ◽  
Carbon Black ◽  
Abrasion Resistance ◽  
Volume Loading ◽  
Rubber Compounds ◽  
Before And After ◽  
The Matrix ◽  
The Many ◽  
Tear Resistance

Abstract The presence of pigments in rubber compounds produces physical properties which are of importance both before and after vulcanization. The ability of the unvulcanized mixture to calender or extrude smoothly with minimum swelling and to maintain shape during air cures, and the tensile strength, tear resistence, and abrasion resistance of vulcanized stocks all are affected. The methods by which these changes are brought about have been considered by many investigators and have been summarized by Parkinson1 and by Shepard, Street, and Park. Since carbon black is the most generally useful reinforcing pigment, it is natural that investigations have been directed particularly to this product. However, while it is recognized that differences exist in the final properties imparted by different pigments, all solid compounding ingredients have something in common. This point can be illustrated by the tear resistance imparted by such a variety of pigments as carbon black, zinc oxide, whiting, and clay. The effect of volume loading on the tear resistance of vulcanized stocks containing these materials, determined by the method of Zimmerman is shown in Figure 1. The effect of solid compounding ingredients can be studied only by considering the compound as a whole, since the properties are determined very largely by the relation between the solid particle and the matrix which surrounds it. Since the introduction of the many types of synthetic rubbers, the complexity of the problem has been greatly increased by the different states of polymerization, which affect the ability of the rubber to conform to the shape of the pigment particle and by the differences in polar nature which affect the type and the degree of adhesion between filler and matrix.

Dielectric Measurements in the Study of Carbon Black and Zinc Oxide Dispersion in Rubber

1939 ◽  
Vol 12 (2) ◽  
pp. 317-331
Author(s):  
A. R. Kemp ◽  
D. B. Herrmann
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
Zinc Oxide ◽  
Dielectric Properties ◽  
Carbon Black ◽  
Water Soluble ◽  
Oxide Dispersion ◽  
Dielectric Measurements ◽  
Thermal Decomposition Process ◽  
Rubber Compounds

Abstract The dielectric constant, power factor, conductivity and d.c. resistivity of rubber compounds containing various types and quantities of zinc oxide and carbon pigments have been measured. It has been shown that the dielectric properties of rubber compounds having high loadings of zinc oxide depend on the particle size and purity of the zinc oxide used. The French process oxides with the smallest particle size were found superior to other grades. Water-soluble impurities in zinc oxide are shown to have a deleterious effect on dielectric properties, especially in the presence of moisture. The effect on dielectric properties of adding carbon black to a rubber compound has been shown to be dependent on the type and amount of black added, and on the nature of its dispersion in the rubber. The dielectric properties of rubber compounds containing “soft” black made by the thermal decomposition process are shown to be distinctly superior to, and widely different from, those of the same compounds containing equal amounts of channel process black. The general conclusion has been reached that the smaller the particle size and the better the dispersion of carbon pigments in the rubber, the greater will be the increase in the dielectric constant and conductivity, and the greater will be the decrease in resistivity.

Effects of Processing Variables on the Mechanical Properties of Carbon Black Filled Rubber

1978 ◽  
Vol 51 (5) ◽  
pp. 1006-1022 ◽  
Author(s):  
B. Wijayarathna ◽  
W. V. Chang ◽  
R. Salovey
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Secondary Structure ◽  
Carbon Black ◽  
Term Structure ◽  
Primary Structure ◽  
Filler Particle ◽  
Structural Heterogeneity ◽  
Mixing Process ◽  
High Structure

Abstract Vulcanizate properties such as tensile strength, abrasion resistance, and tear resistance, are often enhanced by the introduction of structural heterogeneity. This is usually achieved by incorporating fillers into the polymer matrix. In addition to the type of filler and polymer used, mechanical properties depend on factors such as filler particle size, distribution, filler-polymer interaction, and network homogeneity. These factors are largely governed by the conditions of the mixing. The most widely used filler in rubber is carbon black. Carbon black, produced by the pyrolysis of hydrocarbons, is in the form of fused primary aggregates which flocculate to form large secondary aggregates held together by van der Waal forces. The term structure, as applied to carbon black, commonly refers to both primary and secondary aggregates and is designated as primary or secondary structure. The reinforcement of rubber by carbon black depends considerably on the particle size and structure of the black used. Voet and associates have shown evidence that the primary structure is not broken down by shearing action during mixing. However, Heckman and Medalia and Gessler claim that fracture of the primary structure could result from severe mechanical shear. The general consensus is that breakdown of the primary structure of carbon black is not extensive in the usual mixing process. Boonstra and Medalia, among others, reported that large agglomerates remaining after insufficient mixing have a deleterious effect on the rupture properties of vulcanizates. Hence, an optimal mixing process does not destroy secondary aggregates. The secondary structure plays an important role in the dispersion of carbon black during mixing as rubber is squeezed into both primary and secondary aggregates. Low structure blacks pack much more tightly than high structure ones and are more difficult to disperse.

Swelling Behavior of Rubbers Compounded with Reinforcing Pigments

1959 ◽  
Vol 32 (3) ◽  
pp. 825-843 ◽  
Author(s):  
B. B. S. T. Boonstra ◽  
Eli M. Dannenberg
Keyword(s):  
Carbon Black ◽  
Fumed Silica ◽  
Crosslink Density ◽  
The Other ◽  
Rubber Matrix ◽  
Volume Loading ◽  
Precipitated Silica ◽  
Bound Rubber ◽  
Equilibrium Swelling ◽  
The Matrix

Abstract Equilibrium swelling data are presented for vulcanizates of natural rubber, SBR 1500, butyl rubber, neoprene, and nitrile rubber containing fumed silica, precipitated silica, precipitated calcium metasilicate, hard clay and carbon black. Swelling media are chloroform, benzene, hexane, and acetone. It is observed that certain fillers, particularly carbon black, cause a reduction in the swelling of the rubber matrix which is commensurate with the volume loading of the filler. This effect is not specific for a particular solvent or elastomer. When a series of loadings of a filler shows this effect of reducing the matrix swelling in one solvent, it is also shown by the swelling data for the other solvents, but not to the same degree. The system SBR-benzene was studied to determine from the bound rubber measurements and the equilibrium swelling data for the corresponding vulcanizates the number of crosslinks per cubic centimeter in the unvulcanized and vulcanized states. It appears that the number of crosslinks estimated in the bound rubber gel is much too small to account for the increase in crosslink density in the rubber matrix that is caused by the presence of carbon black in the vulcanizate.

Atomic Force Microscopy of Elastomers: Morphology, Distribution of Filler Particles, and Adhesion Using Chemically Modified Tips

1999 ◽  
Vol 72 (5) ◽  
pp. 862-875 ◽  
Author(s):  
D. Trifonova-Van Haeringen ◽  
H. Schönherr ◽  
G. J. Vancso ◽  
L. van der Does ◽  
J. W. M. Noordermeer ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Carbon Black ◽  
Rubber Matrix ◽  
Phase Imaging ◽  
Silane Coupling Agents ◽  
Force Microscopy ◽  
Chemically Modified ◽  
Atomic Force ◽  
Silica Filler ◽  
Filler Particles

Abstract The microdispersion of silica and carbon black-based filler particles in unvulcanized and vulcanized ethylene-propylene-diene terpolymer (EPDM) rubbers was investigated by atomic force microscopy (AFM). Tapping mode phase imaging was found to be particularly useful for imaging of the filler aggregates and for the visualization of single primary filler particles. It was demonstrated that the use of silane coupling agents significantly improves the microdispersion of silica filler in the rubber matrix, as compared to (a) silica without coupling agent, and (b) to carbon black. These results correlate very well with the observed mechanical properties of the materials. In addition, adhesion imaging and the analysis of measured pull-off forces allowed us to differentiate between the filler particles and the rubber matrix, as well as between different types of filler particles. The application of chemically modified AFM tips in pull-off force measurements allowed us to monitor the increase of the hydrophilicity as a result of plasma treatment of the surface of crosslinked poly(dimethylsiloxane), and as a result of chlorination of butyl rubber.

Hydrothermal Sulfidation of Hemimorphite with Elemental Sulfur

2013 ◽  
Vol 634-638 ◽  
pp. 106-111
Author(s):  
Cun Xiong Li ◽  
Chang Wei ◽  
Zhi Gan Deng ◽  
Min Ting Li ◽  
Xin Bing Li ◽  
...  
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Zinc Oxide ◽  
Elemental Sulfur ◽  
Metal Sulfide ◽  
Agitation Speed ◽  
Hydrothermal Conditions ◽  
Zinc Recovery ◽  
Flotation Process ◽  
Temperature Time

Direct flotation of zinc oxide ore is characterized by poor recovery of only around 50% of zinc. Hydrothermal sulfidation of hemimorphite with elemental sulfur resulted in the formation of stable metal sulfide compounds that would enhance zinc recovery by flotation process. The variables considered in the study were sulfur dosage, temperature, time, stirring speed and particle size. Temperature was the most important factor. The experimental data indicated that under the hydrothermal conditions with sulfur dosage 1.2, temperature 220 °C, time 180 min, agitation speed 500rpm and particle size74-106μm, and 73% hemimorphite conversion fraction was achieved.

Prediction of Bound-Rubber Modulus by Clausius—Mossotti Approximation

1990 ◽  
Vol 63 (4) ◽  
pp. 523-539 ◽  
Author(s):  
J. J. Scobbo
Keyword(s):  
Carbon Black ◽  
Mechanical Model ◽  
Electromagnetic Theory ◽  
Rubber Matrix ◽  
Hydrodynamic Volume ◽  
Uniform Layer ◽  
Carbon Black Concentration ◽  
Bound Rubber ◽  
Filler Particles ◽  
Spherical Filler

Abstract The Clausius—Mossotti approximation has been used to determine the modulus of bound rubber attached to carbon black in a gum-rubber/carbon-black compound. The effective hydrodynamic concentration of the carbon-black/bound-rubber structure was first determined based on the assumption of spherical filler particles with a uniform layer of bound rubber on the surface. The true carbon-black concentration was then subtracted from this concentration, and a three component modeling scheme was used. The three components were considered to be bound-rubber, carbon black, and gum-rubber matrix. The Clausius—Mossotti approximation was used to determine the bound-rubber modulus that would give the same compound modulus based on equivalent hydrodynamic volume. Results indicate that bound-rubber concentration decreases with increasing strain. At zero strain, the bound-rubber concentration is approximately equal to the carbon-black concentration. Modulus values of bound rubber were found to be 3 to 4 times greater than gum-modulus values at very low strains. The relatively greater magnitude of bound-rubber modulus decreased with increasing strain until the filler effect appears to be almost purely hydrodynamic. The electromagnetic theory-based Clausius—Mossotti model was found to predict bound-rubber moduli that were in agreement with a mechanical model, the Kerner model.

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