Solvent Crack Growth in NBR Rubber

1976 ◽  
Vol 49 (5) ◽  
pp. 1324-1347 ◽  
Author(s):  
K. Nakashima ◽  
K. Manabe
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Crack Growth ◽  
Linear Function ◽  
Filler Loading ◽  
Square Root ◽  
Extension Ratio ◽  
Straight Lines ◽  
Highly Loaded

Abstract The solvent crack growth of rubber compounded with various carbon blacks or calcium carbonate was investigated. It was found that the rate of crack growth of filler-loaded rubber was linearly related to extension ratio in a manner similar to gum vulcanizates. The rate of crack growth passes through a minimum as the filler loading is increased. It is dependent on the particle size of the filler; smaller particles show much greater effect than coarser ones. When the rates of crack growth of highly loaded samples were plotted against the extension ratio, plots consisting of two straight lines with a bending point were obtained. It was found that the extension ratio at the bending point depended upon the loading and particle size of filler. It was a linear function of the square root of the distance between filler particles. The slope of the line above the bending point varies with type of filler: with carbon black the slope is steeper; with calcium carbonate it is less steep.

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.

The Influence of Carbon Black on the Reversion Process in Sulfur-Accelerated Vulcanization of Natural Rubber

1982 ◽  
Vol 55 (1) ◽  
pp. 103-115 ◽  
Author(s):  
C. H. Chen ◽  
J. L. Koenig ◽  
J. R. Shelton ◽  
E. A. Collins
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Carbon Black ◽  
Natural Rubber ◽  
Linear Function ◽  
Operating Conditions ◽  
Universal Curve ◽  
Black Particle ◽  
System Operating

Abstract The effect of carbon black upon the reversion process in the sulfur-accelerated vulcanization of natural rubber has been studied. It is found that black-filled cure systems have a faster rate of vulcanization and better reversion resistance. The net decrease of trans-methine content, which is equivalent to the improvement of reversion resistance, is found to be at most 15%, with the initial 10 pphr loading yielding the greatest effect. However, those decreases of trans-methine content are small when compared with the substantial effects of these fillers on the physical-mechanical properties of the vulcanizate, which is a linear function of black loading. In general, the smaller the black particle size, the greater the improvement of the reversion resistance, but particle size alone is not the only factor affecting reversion. A universal curve is obtained for correlating the amount of reversion and trans-methine content, which is independent of any natural rubber-based curing system, operating conditions and type of fillers.

Effect of palmyra palm fiber filler on properties of natural rubber vulcanizate

2014 ◽  
Vol 11 (6) ◽  
pp. 565-574
Author(s):  
J. Nwabanne ◽  
P. Igbokwe ◽  
E. Ezeonyebuchi
Keyword(s):  
Particle Size ◽  
Carbon Black ◽  
Natural Rubber ◽  
Surface Area ◽  
Filler Loading ◽  
Partial Replacement ◽  
Average Particle ◽  
Swelling Properties ◽  
Palm Fiber ◽  
Loading Ratio

The effect of partial replacement of carbon black by Palmyra palm fiber on the cure characteristics, physico-mechanical and swelling properties of natural rubber vulcanizates was studied. The Palmyra palm fibers were extracted, treated and characterized so as to determine pH, moisture content, and ash content, loss on ignition, conductivity, cellulose, lignin, Hemicellulose, cellulose/lignin ratio and Acid soluble lignin. The functional groups in the Palmyra palm fiber was also determined using FTIR. The Palmyra palm powder with an average particle size of 75 μm was used in this study. The natural rubber/carbon black/Palmyra palm fiber (NR/CB/PPF) composites having eight different loadings, 0/70, 10/60, 20/50, 30/40, 40/30, 50/20, 60/10, 70/0, were prepared using a laboratory size two roll mill. The maximum Torque of NR/CB/PPF composites increased with increasing commercial filler loading ratio. The scorch time and cure time of NR/CB/PPF composites decreased as the ratio of CB loading increased. The tensile strength, modulus of elongation, tear strength and abrasion resistance of all the composites increased as the commercial filler loading ratio increased. This is due to the presence of the commercial filler which gave a better filler interaction. Also this behavior can be attributed to the particle size and surface area of the fillers used as the fillers with small particle size usually have a larger surface area which supports better filler-rubber interaction. The hardness increased as the palmyra palm fiber loading increased. The elongation at break decreases as carbon black filler loading increases except for the composite with CB/PPF ratio of 10/60. The effect of filler loading on the swelling behavior of NR/CB/PPF composites was also investigated in aromatic and aliphatic compounds. Result showed that the composites with more carbon black has less absorption than those with more palmyra palm fiber showing that the compounds with more carbon black has better interaction than those with palmyra palm fiber.

Compressive Deformation and Energy Absorption Characteristics of Conductive Carbon Black Reinforced Microcellular EPDM Vulcanizates

2005 ◽  
Vol 24 (4) ◽  
pp. 209-222 ◽  
Author(s):  
S.P. Mahapatra ◽  
D.K. Tripathy
Keyword(s):  
Carbon Black ◽  
Compressive Stress ◽  
Energy Absorption ◽  
Filler Loading ◽  
Maximum Efficiency ◽  
Stress Strain ◽  
Blowing Agent ◽  
Compression Set ◽  
Rate Dependent ◽  
Conductive Carbon Black

Compressive stress-strain properties of unfilled and conductive carbon black (VulcanXC 72) filled oil extended EPDM (keltan 7341A) microcellular vulcanizates were studied as a function of blowing agent (density) and filler loading. With decrease in density, the compressive stress-strain curves for microcellular vulcanizates behaved differently from those of solid vulcanizates. The compressive stress-strain properties were found to be strain rate dependent. The log-log plots of relative density of the microcellular vulcanizates showed a fairly linear correlation with the relative modulus. The compression set at a constant stress increased with decrease in density. The efficiency of energy absorption E, was also studied as a function of filler and blowing agent loading. From the compressive stress-strain plots the efficiency E and the ideality parameter I, were evaluated. These parameters were plotted against stress to obtain maximum efficiency and the maximum ideality region, which will make these materials suitable for cushioning and packaging applications in electronic devices.

Particle Size, Structure and Powdering Process of Calcium Carbonate Nanoparticles Filled Powdered Styrene-Butadiene Rubber

2011 ◽  
Vol 415-417 ◽  
pp. 237-242
Author(s):  
Zhou Da Zhang ◽  
Xue Mei Chen ◽  
Guo Liang Qu
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Size Structure ◽  
Average Diameter ◽  
Rubber Matrix ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Particle Structure ◽  
Styrene Butadiene ◽  
New Particles

Calcium carbonate nanoparticles (nano-CaCO3) filled powdered styrene-butadiene rubber (P(SBR/CaCO3) was prepared by adding nano-CaCO3 particles, encapsulant and coagulant to styrene-butadiene rubber (SBR) latex by coacervation, and the particle size distribution, structure were studied. Scanning electron microscopy (SEM) was used to investigate the (P(SBR/CaCO3) particle structure, and a powdering model was proposed to describe the powdering process. The process includes: (i) the latex particles associated with the dispersed nano-CaCO3 particles (adsorption process) to form “new particles” and (ii) the formation of P(SBR/CaCO3) by coagulating “new particles”. The SEM results also shown that the nano-CaCO3 and rubber matrix have formed a macroscopic homogenization in the (P(SBR/CaCO3) particles and nano-CaCO3 dispersed uniformly in the rubber matrix with an average diameter of approximately 50 nm.

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.

scholarly journals Nutrient accumulation and biomass production of alfafa after soil amendment with silicates

Revista CERES ◽  
2014 ◽  
Vol 61 (3) ◽  
pp. 406-413 ◽  
Author(s):  
Angélica Cristina Fernandes Deus ◽  
Leonardo Theodoro Bull ◽  
Juliano Corulli Corrêa ◽  
Roberto Lyra Villas Boas
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Soil Amendment ◽  
Soil Acidity ◽  
Steel Slag ◽  
The Other ◽  
Chemical Characteristics ◽  
Nutrient Accumulation ◽  
Particle Size Fractions ◽  
Soil Liming

Studies on the use of silicate correctives in agriculture show that they have great potential to improve soil chemical characteristics, however, little information is available on the reactivity rates of their particle-size fractions. This study investigated whether the reactivity rates obtained experimentally could be considered in the calculation of ECC (effective calcium carbonate) for soil liming, promoting adequate development of alfalfa plants. Six treatments were evaluated in the experiment, consisting of two slag types applied in two rates. The experimental ECC was used to calculate one of the rates and the ECC determined in the laboratory was used to calculate the other. Rates of limestone and wollastonite were based on the ECC determined in laboratory. The rates of each soil acidity corretive were calculated to increase the base saturation to 80%. The treatments were applied to a Rhodic Hapludox and an Alfisol Ferrudalfs. The methods for ECC determination established for lime can be applied to steel slag. The application of slag corrected soil acidity with consequent accumulation of Ca, P, and Si in alfalfa, favoring DM production.

Effects of Rotation Speeds and Media Density on Ground Calcium Carbonate during Ultrafine Grinding Process in Planetary Mill

2014 ◽  
Vol 997 ◽  
pp. 542-545
Author(s):  
Yan Ru Chen ◽  
Yi Chen Lu ◽  
Xiao Min Lian ◽  
Chao Yang Li ◽  
Shui Lin Zheng
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Rotational Speed ◽  
Planetary Mill ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dry Grinding ◽  
Ultrafine Grinding ◽  
Effects Of Rotation ◽  
Ground Calcium Carbonate

Superfine ground calcium carbonate (GCC) produced by carbonate minerals is a widely used inorganic powder material. In order to get a finer GCC powder with narrow distribution span, the effect of rotational speed and media density on ground GCC were studied by dry grinding GCC in a planetary ball mill under different rotational speed and various media density. The grinding limit-particle size and distribution of grinding calcium carbonate were measured by centrifugal sedimentation granulometer. The structure of GCC was measured by X-ray diffraction. The result shows that low rotational speed and high-density media is conducive to get a product with smaller particle size and narrow size distribution; crystal plane (012) and (122) are more stable than (018) and (116).

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