Influence of Carbon Black on Processability of Rubber Stocks III. Extensional Viscosity

1978 ◽  
Vol 51 (4) ◽  
pp. 749-763 ◽  
Author(s):  
G. R. Cotten ◽  
J. L. Thiele
Keyword(s):  
Stress Relaxation ◽  
Carbon Black ◽  
Surface Area ◽  
Flow Curve ◽  
High Surface ◽  
Extensional Flow ◽  
Viscosity Coefficient ◽  
Extensional Viscosity ◽  
Relaxation Rates ◽  
New Instrument

Abstract A new instrument for measurement of extensional viscosity was designed and employed in the evaluation of SBR compounds containing carbon black and other non-black fillers. It was shown that carbon black filled rubbers generally do not reach steady-state viscosity ; the stress continues to increase with increasing strain up to the point of rupture, due to rapid orientation of molecular chains during extensional flow. The data was evaluated in terms of the Denn-Marrucci equation, and the effect of carbon black on the two adjustable parameters was found. It was found that higher carbon black loading or structure increases only the viscosity coefficient, i.e., it changes the relative level of the flow curve without changing its shape. On the other hand, an increase in surface area increases both the viscosity coefficient and the relaxation time, i.e., it increases the upward curvature of the flow curve. A very good correlation was observed between Mooney viscosity values and calculated viscosity coefficients. Some agreement was found between calculated relaxation times and the rates of stress relaxation for rubbers containing nonblack fillers, while in carbon black loaded stocks the observed differences in stress relaxation rates were too small to draw definite conclusions. The use of high surface area, low structure carbon black is recommended for applications where stiffening of the SBR compounds during extension is desired.

Influence of Carbon Black on Processability of Rubber Stocks. IV. Kinetics of Extrusion Shrinkage

1979 ◽  
Vol 52 (1) ◽  
pp. 199-206 ◽  
Author(s):  
G. R. Cotten
Keyword(s):  
Carbon Black ◽  
Surface Area ◽  
Elastic Recovery ◽  
Extensional Flow ◽  
Relaxation Times ◽  
Flow Region ◽  
Careful Examination ◽  
Relaxation Processes ◽  
Relaxation Rates ◽  
Slow Recovery

Abstract A careful examination of post-extrusion relaxation rates of SBR compounds containing various carbon blacks has shown that two distinct relaxation processes are taking place. The fast recovery region observed at times of less than 0.1 s after exit from the die is thought to be due to solid-like elastic recovery of the polymer imposed in the extensional flow region at the entrance to the die. The magnitude of that recovery increases with increasing surface area and decreasing structure of carbon black. The slow recovery region is observed at times longer than 1 s and caused by molecular orientation that occurs mainly during the extensional flow at the die entrance and maintained during the viscous flow through the die. Carbon black surface area and structure do not significantly affect the magnitude of the shrinkage in the slow recovery region. The observed two relaxation mechanisms may be simulated mathematically by two modified Maxwell elements in parallel, whose spring constants (and relaxation times) differ by a large factor.

Relaxation of Stress and Electrical Resistivity in Carbon-Filled Vulcanizates at Moderate and High Extensions

1971 ◽  
Vol 44 (1) ◽  
pp. 185-198 ◽  
Author(s):  
A. K. Sircar ◽  
A. Voet ◽  
F. R. Cook
Keyword(s):  
Particle Size ◽  
Electrical Resistivity ◽  
Stress Relaxation ◽  
Carbon Black ◽  
Carbon Chain ◽  
Relaxation Mechanism ◽  
Initial Increase ◽  
Relaxation Rates ◽  
Carbon Structures ◽  
Chain Alignment

Abstract Measurements have been made of the relaxation of stress and electrical resistivity of stretched carbon black-loaded vulcanizates throughout the elongation range up to break. Data were obtained for vulcanizates with a number of carbon blacks, varying in particle size and in structure. The influence of the degree of loading as well as of the type of elastomer was investigated. In a gum vulcanizate there is initially a decline in rate of stress relaxation at increasing elongation as a result of the limited extensibility of the elastomer chains, followed by a constant rate at higher extensions. The level for a carbon-loaded vulcanizate is always higher than for the gum. At lower elongations this is due to an additional relaxation mechanism, the reformation of broken weak bonds between elastomer and filler particles upon standing. At medium and higher elongations, the stress relaxation rate for the carbon-filled vuleanizates increases sharply with increasing extension, due to persistent carbon chain alignment and, at still higher elongation, to rupture of carbon-elastomer bonds, both phenomena leading to additional modes of stress relaxation. Resistivity relaxation rates reflect changes in carbon black distribution. An initial increase at small extensions is due to rebuilding of destroyed transient structures. A decrease in relaxation rates for medium extension ranges is caused by persistent carbon chain alignment, less pronounced at increasing elongation. At the higher elongations carbon-elastomer bonds arc broken, leading to randomization of chains, resulting in negative relaxation rates with higher structure blacks at the highest elongations. All such effects depend to a large extent on the carbon structures. The influence of loading level, of particle size and of elastomer type is discussed.

scholarly journals Enhancing the Performance of Motive Power Lead-Acid Batteries by High Surface Area Carbon Black Additives

2019 ◽  
Vol 9 (1) ◽  
pp. 186 ◽  
Author(s):  
Hai-Yan Hu ◽  
Ning Xie ◽  
Chen Wang ◽  
Fan Wu ◽  
Ming Pan ◽  
...  
Keyword(s):  
Carbon Black ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Cycle Life ◽  
Cycle Performance ◽  
Discharge Performance ◽  
Negative Plate ◽  
Lead Acid Batteries ◽  
Lead Acid

The effects of carbon black specific surface area and morphology were investigated by characterizing four different carbon black additives and then evaluating the effect of adding them to the negative electrode of valve-regulated lead–acid batteries for electric bikes. Low-temperature performance, larger current discharge performance, charge acceptance, cycle life and water loss of the batteries with carbon black were studied. The results show that the addition of high-performance carbon black to the negative plate of lead–acid batteries has an important effect on the cycle performance at 100% depth-of-discharge conditions and the cycle life is 86.9% longer than that of the control batteries. The excellent performance of the batteries can be attributed to the high surface area carbon black effectively inhibiting the sulfation of the negative plate surface and improving the charge acceptance of the batteries.

scholarly journals Nitrogen functionalized carbon black: A support for Pt nanoparticle catalysts with narrow size dispersion and high surface area

Carbon ◽  
2015 ◽  
Vol 81 ◽  
pp. 115-123 ◽  
Author(s):  
Suzanne S. Rich ◽  
Jonathan J. Burk ◽  
Chang Sun Kong ◽  
Cynthia D. Cooper ◽  
Daniel E. Morse ◽  
...  
Keyword(s):  
Carbon Black ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Pt Nanoparticle ◽  
Nanoparticle Catalysts ◽  
Size Dispersion

scholarly journals Effect of temperature and surface area on adsorption of chlorine on different adsorbent carbons

2012 ◽  
Vol 4 (2) ◽  
pp. 284-287
Author(s):  
Prem Kumari Gupta
Keyword(s):  
Carbon Black ◽  
Surface Area ◽  
Activated Carbons ◽  
Dominant Role ◽  
High Surface ◽  
Effect Of Temperature ◽  
Residual Chlorine ◽  
Active Carbons ◽  
Coconut Charcoal ◽  
Two Samples

Chlorine is used in several ways in industry. In such situations, where residual chlorine persists as pollutant, Activated carbons like animal charcoal, carbon black and coconut charcoal can serve as agents to remove residual pollutant “chlorine” by the process of adsorption. Five samples of Carbon black, six samples of active Carbons and two samples of charcoals were treated with a stream of chlorine @0.4 litre/hour at temperature varying from 300 to 1200 C. Chlorine is adsorbed partially physically and partially chemically. Percentage of the chemisorbed increases with rise in the temperature. Maximum percentages of chemisorptions occur at 1200 C while the maximum uptake, physical as well as chemical, takes place at 300 C, which was the lowest temperature. It is seen that activated carbon, carbon blacks and charcoal differ markedly by in their total chlorine uptake at 300 C. Activated carbons associated with high surface were seen to take up maximum chlorine. Fall in surface area is more in active carbons as compared to carbon black due to greater adsorption of chlorine. This probably shows that micro porous carbons are better adsorbent for chlorine adsorption. The unsaturated sites also play far dominant role and provide centres where the adsorption takes place predominantly. Uptake of chlorine is enhanced on evacuating the carbon samples at 6000 C and 10000 C. This is due to the creation of more unsaturated sites. Process of adsorption cum chemisorption takes place through different kinetic stages with different energetics. The activation energies keep on increasing with increasing amounts of chemisorption.

Synthesis of High Surface Area Calcium Aluminate (Ca12Al14O33) with Carbon Template by Solid State Calcination Method

2019 ◽  
Vol 41 (4) ◽  
pp. 664-664
Author(s):  
Ruiyuan Tang Ruiyuan Tang ◽  
Junhui Hao Junhui Hao ◽  
Kai Liu Kai Liu ◽  
Yingyun Qiao Yingyun Qiao ◽  
Juntao Zhang and Yuanyu Tian Juntao Zhang and Yuanyu Tian
Keyword(s):  
Solid State ◽  
Carbon Black ◽  
Surface Area ◽  
Calcium Aluminate ◽  
High Surface ◽  
High Surface Area ◽  
Textural Properties ◽  
Cost Effective ◽  
Carbon Template ◽  
Calcination Method

High surface area calcium aluminate is synthetized within a short time by using a carbon template solid state calcination method which involved addition of carbon black into the CaCO3 and Al2O3 powders, calcination, and carbon removal by steam. Vary carbon black dosage changed the textural properties of the calcium aluminate, such as the surface area. By varying carbon black dosage from 0 to 10.0 wt%, the calcium aluminate with a surface area ranging from 21.5 to 41.2 m2and#183;g–1 are successfully synthesized within 14.0 h. Furthermore, the nanometer sized CaCO3 and Al2O3 powders comprising carbon black could markedly reduce the calcination temperature without reducing the surface area. This research might lead to the cost-effective synthesis of calcium aluminate (Ca12Al14O33) in a short synthesis period.

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