Effect of Carbon Black on the Development of Oxidation Processes in Raw and Vulcanized Rubbers

1953 ◽  
Vol 26 (4) ◽  
pp. 858-861 ◽  
Author(s):  
A. S. Kuzmixskiĭ ◽  
L. I. Lyubchanskaya ◽  
N. G. Khitrova ◽  
S. I. Bass
Keyword(s):  
Carbon Black ◽  
Chain Process ◽  
Butadiene Rubber ◽  
Chain Reactions ◽  
Oxidation Processes ◽  
Carbon Blacks ◽  
Developed Surface ◽  
A Chain ◽  
Reaction Vessels

Abstract Publications by Rebinder, Ab, and Vei˘ler, Pisarenko and Rebinder, and Dogadkin, Pechkovskaya, and Chernikina have been devoted to an explanation of the mechanism of the accelerating action of carbon blacks. However, only fragmentary and contradictory information about the influence of carbon blacks on the development of oxidation processes is found in scientific literature. In the present article, several important laws regarding the role of channel carbon black in the oxidation of sodium-butadiene rubber are studied. Carbon black can be incorporated in rubber in high proportions (100–125 parts by weight to 100 parts of rubber). It is well known how great is the influence of the surface area of reaction vessels in which the rupture of chains takes place on the development of chain reactions. It is also known that the oxidation of any type of rubber is a chain process of decomposition, with formation of side chains. Therefore in the study of these processes in rubbers, it is necessary to take into account the highly developed surface of contact between the carbon black and rubber particles.

Antioxidant Properties of Carbon Black in Unsaturated Elastomers. Studies with cis-Polybutadiene

1965 ◽  
Vol 38 (3) ◽  
pp. 636-646
Author(s):  
J. T. Gruver ◽  
K. W. Rollmann
Keyword(s):  
Antioxidant Activity ◽  
Carbon Black ◽  
Antioxidant Properties ◽  
Chain Scission ◽  
Oxygen Absorption ◽  
Hydroxyl Groups ◽  
Carbon Blacks ◽  
Crosslinking Reactions ◽  
Absorption Measurements

Abstract The thermal antioxidant behavior of carbon black was studied in vulcanized cis-polybutadiene and related to the surface chemistry of the black. Continuous and intermittent stress relaxation and oxygen absorption measurements were employed to determine the antioxidant ability of the carbon blacks. The blacks were characterized by the surface concentrations of oxygen-containing functional groups, using methods described in the literature. Antioxidant activity was found to be highest in carbons containing relatively large amounts of bound oxygen. These carbons are also acidic and decompose peroxides by the ionic mechanism. This was demonstrated with cumyl peroxide. However, even though the acidity and ability to decompose cumyl peroxide to phenol and acetone could be destroyed by methylation, this treatment did not seriously impair the antioxidant activity, so that the role of acidic groups appears to be minor. Evidence is presented which suggests strongly that the antioxidant behavior of carbon blacks is due to surface quinones, possibly hydrogen-bonded with adjacent hydroxyl groups. Measurements made on samples vulcanized in peroxide and sulfur curing systems indicate that the antioxidant behavior of carbon black is independent of the method of vulcanization in the absence of other antioxidants. A characteristic feature of the antioxidant action of carbon blacks is their tendency to repress the oxidative crosslinking reactions, the relative amount of compensation of chain scission by crosslinking being smaller than in gum vulcanizates.

Mixing of Carbon Black with Rubber I. Measurement of Dispersion Rate by Changes in Mixing Torque

1984 ◽  
Vol 57 (1) ◽  
pp. 118-133 ◽  
Author(s):  
George R. Cotten
Keyword(s):  
Carbon Black ◽  
Volume Fraction ◽  
Small Samples ◽  
Butadiene Rubber ◽  
Mixing Process ◽  
Carbon Blacks ◽  
Bound Rubber ◽  
Power Peak ◽  
Dispersive Mixing ◽  
Carbon Black Dispersion

Abstract Analysis of the torque data obtained for a large range of carbon blacks in an oil-extended butadiene rubber (CB-441) shows that the rate of decrease of torque (after the second power peak) follows first order kinetics. The rate of decrease represents the rate of reduction in effective filled volume fraction through dispersion of carbon black agglomerates, and thus, a reduction in the volume of rubber occluded between individual aggregates within the agglomerates. The assumption that the rate of torque reduction is proportional to the rate of carbon black dispersion was tested by examining the responses to various factors influencing the mixing process. In general, the conclusions reached from the analysis of torque data were in agreement with the common industrial experience and predictions based on the mathematical analysis of dispersive mixing. Tadmor's analysis of dispersive mixing predicts that the rate of agglomerate rupture depends on the number of particle-particle contacts and thus is related to the size of individual aggregates, but is independent of agglomerate size. Thus, it is in agreement with the present findings that the rate of dispersive mixing increases with decreasing surface area and increasing structure of aggregates. Increasing polymer-filler interaction gives rise to a faster rate of dispersive mixing, possibly by increasing the effective radii of aggregates through bound rubber formation. Increasing the batch temperature increases the rate of dispersive mixing due to reduced cohesion between the aggregates and a more favorable balance between cohesive and shearing forces. Increasing carbon black loading increases the rate of dispersive mixing by increasing the viscosity and, thus, shearing forces generated during the mixing process. The technique developed in this work may provide a better means for measuring dispersibility of carbon blacks, since other available methods suffer certain disadvantages. For instance, the resistivity measurements are not only dependent on carbon black dispersion, but also on the chemical nature of its surface, while microscopic methods depend on the examination of very small samples that may not be representative of the whole batch.

scholarly journals The kinetics of the reaction between hydrogen and nitrous oxide.─I

1933 ◽  
Vol 142 (847) ◽  
pp. 524-545 ◽  
Keyword(s):  
Nitrous Oxide ◽  
Kinetic Method ◽  
Gaseous Mixture ◽  
Theoretical Treatment ◽  
Chain Process ◽  
Combustion Chemistry ◽  
Chain Reactions ◽  
Simple Molecules ◽  
A Chain ◽  
Kinetics Of

Until about five years ago, the theoretical treatment of the mechanism of the oxidation of simple molecules had been comparatively neglected. Prior to this, however, considerable progress had been made in the study of the kinetics of thermal and photochemical gas reactions. That knowledge has now been successfully applied and extended to solve some of the major problems in combustion chemistry, and thereby has given rise to the development of the theory of thermal chain reactions. Hitherto, the investigation of these reactions has been confined almost entirely to oxidations by molecular oxygen. It is known, however, that many gases ignite in:nitrous oxide at about the same temperature as they do in oxygen, and it might be anticipated that here, too, a chain process is in operation. The object of studying the interaction of hydrogen and nitrous oxide was to determine whether it is a chain reaction, and if so, to make a detailed analysis of its mechanism by the kinetic method. One of the first criteria in looking for the possibility of the propagation of chains in a gaseous mixture is that the reaction must be exothermic. This condition is amply fulfilled in the present instance, for 75 k. cal. are liberated per mole of water formed. Indeed, the reaction is even more exothermic than the formation of one mole of water from hydrogen and oxygen, when only 50 k. cal. are evolved. This greater exothermicity is due to the fact that 45 k. cal. required to dissociate 1 mole of N 2 O N 2 and O, whereas the production of 1 mole of O atoms from O 2 required about 60 k. cal.

The thermal decomposition of diethyl ether. I. Rate-pressure relations

1958 ◽  
Vol 245 (1240) ◽  
pp. 28-39 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Diethyl Ether ◽  
Order Rate Constant ◽  
Inert Gases ◽  
Chain Process ◽  
Chain Reactions ◽  
First Order ◽  
Molecular Reaction ◽  
A Chain ◽  
Reduced Rate

In the thermal decomposition of diethyl ether the first-order rate constant ( k ) varies with the pressure ( p ) of the ether itself, or that of added hydrogen, or that of various chemically inert gases according to a more complex pattern than has hitherto been supposed. In general, k increases approximately linearly with p X over a certain range: the slope of the curve then decreases as though a limit were being approached. When X refers to ether, hydrogen or certain other gases no limit is in fact reached, but k continues to increase at a considerably reduced rate. With certain gases, however, the slope of the curve becomes very small or zero. Changes in k are not explicable by variations in the chemical composition of the products. The forms of the k-p curves are qualitatively similar for the uninhibited reaction (largely a chain process) and for the nitric oxide-inhibited reaction (hypothetical molecular reaction), but the effects are quantitatively quite different. The k-p relations for the molecular reaction conform to those recently established for the decomposition of paraffins and of nitrous oxide, and may possibly be interpreted by the extended theory of unimolecular reactions proposed for these examples. The relations for the chain reactions are more complicated but the interpretation probably includes considerations similar to the above, applied to the initial molecular process by which the chains start.

Filler-Elastomer Interactions. Part VIII. The Role of the Distance between Filler Aggregates in the Dynamic Properties of Filled Vulcanizates

1993 ◽  
Vol 66 (2) ◽  
pp. 178-195 ◽  
Author(s):  
Meng-Jiao Wang ◽  
Siegfried Wolff ◽  
Ewe-Hong Tan
Keyword(s):  
Gas Chromatography ◽  
Carbon Black ◽  
Inverse Gas Chromatography ◽  
Dynamic Properties ◽  
Random Packing ◽  
Attractive Potential ◽  
Carbon Blacks ◽  
Filled Rubber ◽  
Tan Δ

Abstract Based on the concepts of the occlusion of rubber and random packing of spheres whose volume is equivalent to that permeated by individual aggregates, an equation was deduced to estimate the distance between carbon-black aggregates in filled rubber. It was found that when the interaggregate distance reaches a critical point which is approximately identical for all carbon blacks investigated (furnace blacks), the elastic modulus measured at very low strain deviates from the modified Guth-Gold equation. Tan δ and resilience are mainly determined by the distance between aggregates. These phenomena are related to filler networking which is determined by the attractive potential and the distance between individual aggregates. Since the factor Sf, used to characterize the strength of secondary filler networks in hydrocarbon rubbers and measured by means of inverse gas chromatography, is approximately the same for all furnace blacks, the interaggregate distance seems to determine filler networking. A comparison of fillers with different Sf (graphitized vs. nongraphitized carbon blacks, carbon black vs. silica) shows that at the same interaggregate distance, a lower Sf leads to higher tan δ of the filled vulcanizates.

scholarly journals Enhancement of Chloroprene/Natural/Butadiene Rubber Nanocomposite Properties Using Organoclays and Their Combination with Carbon Black as Fillers

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1085
Author(s):  
Patricia Castaño-Rivera ◽  
Isabel Calle-Holguín ◽  
Johanna Castaño ◽  
Gustavo Cabrera-Barjas ◽  
Karen Galvez-Garrido ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
High Performance ◽  
Rubber Matrix ◽  
Butadiene Rubber ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rubber Blends ◽  
Ft Ir ◽  
Chloroprene Rubber

Organoclay nanoparticles (Cloisite® C10A, Cloisite® C15) and their combination with carbon black (N330) were studied as fillers in chloroprene/natural/butadiene rubber blends to prepare nanocomposites. The effect of filler type and load on the physical mechanical properties of nanocomposites was determined and correlated with its structure, compatibility and cure properties using Fourier Transformed Infrared (FT-IR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and rheometric analysis. Physical mechanical properties were improved by organoclays at 5–7 phr. Nanocomposites with organoclays exhibited a remarkable increase up to 46% in abrasion resistance. The improvement in properties was attributed to good organoclay dispersion in the rubber matrix and to the compatibility between them and the chloroprene rubber. Carbon black at a 40 phr load was not the optimal concentration to interact with organoclays. The present study confirmed that organoclays can be a reinforcing filler for high performance applications in rubber nanocomposites.

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