Reactions of Polymers in Bulk. II. Influence of Crosslink Density on the Mechanical Deformation Properties of Filled Vulcanizates

1962 ◽  
Vol 35 (3) ◽  
pp. 572-580
Author(s):  
J. Janacek
Keyword(s):  
Carbon Black ◽  
Crosslink Density ◽  
Mechanical Deformation ◽  
Physical Effect ◽  
Carbon Blacks ◽  
Deformation Properties ◽  
The Difference

Abstract The mechanical deformation properties as characterized by the modulus at different deformation, hardness and rebound elasticity, were observed in elastomers filled with different carbon-black concentrations referred to the concentration of the effective chains of the rubber network as determined by swelling. The extent of the physical effect of carbon blacks in the elastomers was expressed by the difference between the mechanical deformation values of the filled and unfilled vulcanizates determined at a constant crosslink density.

Processing Ease and Rubber—Carbon-Black Interaction

1988 ◽  
Vol 61 (2) ◽  
pp. 362-376 ◽  
Author(s):  
N. Nakajima ◽  
R. A. Miller
Keyword(s):  
Carbon Black ◽  
Ethyl Acrylate ◽  
Dynamic Mechanical Properties ◽  
Strain Measurements ◽  
Carbon Blacks ◽  
Two Samples ◽  
History Of ◽  
The Difference ◽  
Particle Size And Structure ◽  
Size And Structure

Abstract Two samples of poly(ethyl acrylate) rubber, different in their mill processability and their manner of accepting carbon black were examined. This is a case history of how we differentiated Theological behavior of gum elastomers and how we characterized the rubber—carbon-black interaction in the compound. For the former objective, the dynamic mechanical properties were measured over the temperature range of interest. This information was used to interpret the difference in mill processability. For the latter objective, several carbon blacks in different particle size and structure were compounded with these samples. The effect of the different carbon blacks on these elastomers was examined with tensile stress-strain measurements. At least a part of the differences in behavior could be interpreted as the differences in the interaction between rubber and carbon black.

Continuous Ultrasonic Devulcanization: Comparison of Carbon Black Filled Synthetic Isoprene and Natural Rubbers

2008 ◽  
Vol 81 (1) ◽  
pp. 19-46 ◽  
Author(s):  
Ximei Sun ◽  
A. I. Isayev
Keyword(s):  
Carbon Black ◽  
Power Consumption ◽  
Crosslink Density ◽  
Chain Structure ◽  
Ultrasonic Power ◽  
Gel Fraction ◽  
Fraction Versus ◽  
The Difference ◽  
Lower Torque ◽  
Kinetics Of

Abstract Continuous ultrasonic devulcanization of carbon black (CB) filled isoprene rubber (IR) was carried out. Similar to unfilled IR, power consumption during the devulcanization of the filled IR increased with the increase of ultrasonic amplitude indicating a greater extent of devulcanization. This was in contrast with the devulcanization of CB filled natural rubber (NR) where power consumption showed a maximum at an intermediate amplitude suggesting a lesser extent of devulcanization at higher amplitude. Such a behavior evidently resulted from the difference in the amount of stereoregular structures in the IR and NR rubbers. Gel fraction and crosslink density of the virgin vulcanizates, devulcanizates and revulcanizates were characterized. Kinetics of revulcanization, rheological properties of the devulcanizates and mechanical properties of revulcanizates were compared with those of virgin uncured IR and their vulcanizates. The effect of processing oil on the IR vulcanization, devulcanization and revulcanization was examined indicating a slight delay of the vulcanization and lower torque without affecting the degree of reversion. The addition of oil caused more devulcanization as indicated by an increase in the ultrasonic power consumption and a reduction of the gel fraction and crosslink density of devulcanized rubbers. The revulcanization of the IR occurred without the induction period, regardless of the presence of CB and processing oil. The retarder introduced in the recipe was effective in improving the scorch safety and minimizing the reversion in revulcanization. The experimental data on normalized gel fraction versus crosslink density of filled IR and NR at low CB loadings was found to fall into the master curve, which is probably determined by the main chain structure of both rubbers consisting of cis-1,4 isoprene. At high CB loadings, some differences were observed. The simulation results predicted such a behavior.

Reactions of Polymers in Bulk. V. Deformation Behavior of Vulcanizates Filled with Inorganic Fillers

1962 ◽  
Vol 35 (4) ◽  
pp. 833-838 ◽  
Author(s):  
J. Janacek
Keyword(s):  
Carbon Black ◽  
Deformation Behavior ◽  
Physical Characteristics ◽  
Chemical Activity ◽  
Inorganic Substances ◽  
Deformation Properties ◽  
Inorganic Fillers ◽  
The Difference

Abstract The most marked difference between carbon black and the fillers of inorganic nature is the difference in effect on the interlinking reactions taking place in the rubber. It is shown that the deformation properties of vulcanizates filled with inorganic substances depend upon the same physical characteristics that describe the behavior of carbon black, if the influence of the difference in chemical activity of the fillers is discounted.

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.

A Carbon Black Structure-Concentration Equivalence Principle. Application to Stress-Strain Relationships of Filled Rubbers

1971 ◽  
Vol 44 (1) ◽  
pp. 199-213 ◽  
Author(s):  
Gerard Kraus
Keyword(s):  
Carbon Black ◽  
Primary Structure ◽  
Equivalence Principle ◽  
Chemical Activity ◽  
Cross Linking ◽  
Surface Chemical ◽  
Deformation Structure ◽  
Carbon Blacks ◽  
Filled Rubbers ◽  
Dependent Factor

Abstract It is shown that various modulus values of carbon black reinforced rubber are functions of the product of the actual black loading and a structure dependent factor. The structure factor appears to be a linear function of the so-called 24M4 value of the dibutylphthalate absorption and is independent of elongation, temperature, and degree of cross-linking over the ranges covered by the data reported. An interpretation of the results is offered based on the idea of polymer occluded in the interstices of primary structure aggregates and thereby shielded from deformation. Structure-concentration equivalence can only be demonstrated with carbon blacks differing in (primary) structure alone. Deviations are observed whenever the carbon blacks compared vary significantly in specific surface area and surface chemical activity.

EFFECT OF DEVULCANIZATION ON CROSSLINK DENSITY AND CROSSLINK DISTRIBUTION OF CARBON BLACK FILLED NATURAL RUBBER VULCANIZATES

2016 ◽  
Vol 89 (4) ◽  
pp. 653-670 ◽  
Author(s):  
Anu Mary Joseph ◽  
Benny George ◽  
Madhusoodanan K. N. ◽  
Rosamma Alex
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Crosslink Density ◽  
Morphological Properties ◽  
Original Sample ◽  
Ambient Conditions ◽  
Absolute Value ◽  
Roll Mill ◽  
Percentage Retention ◽  
The Absolute

ABSTRACTCarbon black filled natural rubber (NR) vulcanizates were devulcanized at ambient temperature in a two roll mill. The effect of cure system, that is, conventional vulcanization (CV), semiefficient vulcanization (semi EV), and efficient vulcanization (EV) systems, used for vulcanization of the original sample, on the efficiency of devulcanization was studied. The efficiency of devulcanization expressed as percentage devulcanization of the samples calculated from residual crosslink density measurements was correlated with the sol fraction of the devulcanized samples based on Horikx analysis. Using chemical probe analysis, we determined (i) the crosslink distribution pattern of the original sample, (ii) the extent to which the different types of crosslinks—that is, polysulfidic, disulfidic, and monosulfidic crosslinks—have been debonded or broken during the shearing process in the two roll mill, and (iii) the pattern of bond formation during revulcanization. Mechanical shearing predominantly breaks the majority crosslink type (polysulfidic crosslinks in CV and semi EV cure systems and disulfidic crosslinks in EV samples). Irrespective of the significant reduction in total crosslink density in all three sets of samples, chain shortening reactions similar to the post-crosslinking chemical reactions at curing temperatures also occur during mechanical shear at ambient conditions, which increased the absolute value of monosulfidic links in CV and semi EV systems. However, in the devulcanized EV system, the absolute value of polysulfidic crosslinks increased, which might be due to the re-crosslinking of the cleaved bonds. All the devulcanized samples were revulcanized, and the mechanical and morphological properties were analyzed. The percentage retention of the vulcanizate properties after revulcanization of the devulcanized samples correlated very well with efficiency of devulcanization.

PERMEABILITY STUDIES: III. SURFACE AREA MEASUREMENTS OF CARBON BLACKS

1948 ◽  
Vol 26a (2) ◽  
pp. 29-38 ◽  
Author(s):  
J. C. Arnell ◽  
G. O. Henneberry
Keyword(s):  
Electron Microscope ◽  
Low Temperature ◽  
Carbon Black ◽  
Surface Area ◽  
Satisfactory Agreement ◽  
Nitrogen Adsorption ◽  
Average Particle ◽  
Carbon Blacks ◽  
Permeability Studies ◽  
Nitrogen Adsorption Isotherms

The modified Kozeny equation has been found to be satisfactory for the measurement of the specific surfaces of carbon blacks having average particle diameters ranging from 0.01 to 0.1 μ to within ±10%. Comparative data were obtained from electron microscope counting and from low temperature nitrogen adsorption isotherms. The three methods examined gave results that were in satisfactory agreement, except when the carbon black was porous, and then the adsorption value was extremely large.

CARBON BLACK FOR RACING AND MOTORCYCLE TIRE TREADS. PERFORMANCE MODEL DEVELOPMENT

2011 ◽  
Vol 84 (4) ◽  
pp. 493-506
Author(s):  
Irene S. Yurovska ◽  
Michael D. Morris ◽  
Theo Al
Keyword(s):  
Carbon Black ◽  
Critical Role ◽  
Model Development ◽  
Aggregate Size ◽  
Rolling Resistance ◽  
Performance Model ◽  
Average Life ◽  
Carbon Blacks ◽  
Truck Tires ◽  
And Performance

Abstract Racing tires and motorcycle tires present individual segments of the tire market. For instance, while the average life of car and truck tires is 50 000 miles, the average life of race tires is 100 miles. Because tires play a critical role in a race, technical demands to assure safety and performance are growing. Similarly, tires have a large influence on safety, handling/grip, and performance of the rapidly growing world fleet of motorcycles, due to the fact of only two wheels being in contact with the ground. Thus, the common feature of both market segments is that the typical tire compromise of wear, rolling resistance, and traction is strongly weighted toward traction. Most of the recent efforts of rubber scientists have been directed toward lowering rolling resistance of the tread compounds, which left a certain void in the science of compounding for racing and motorcycle treads. Particularly, the industrial assortment of polymers and fillers used for motorcycle treads is commonly different from that used for car or truck treads, but it is not known how the filler properties affect the hysteresis–stiffness compromise. The objective of this study is to evaluate the effects of the carbon black characteristics on the important properties of a typical racing and motorcycle tire tread compound. More than 50 individual carbon blacks were mixed in a SBR formulation. The acquired data were statistically analyzed, and a linear multiple regression model was developed to relate rubber properties (responses), such as static modulus, complex dynamic modulus, hysteresis, and viscosity to the key carbon black characteristics (variables) of surface area, structure, aggregate size distribution, and surface activity. Prediction profiles created from the model demonstrate rubber performance limits for the range of carbon blacks tested, and indicate the niches to provide required combinations of the rubber properties.

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