Thermally Induced Crosslinking between Polyacrylic Acid and Epoxidised Natural Rubber: Effect of Carbon Black Filler on Strain Dependent Dynamic Mechanical Properties

1994 ◽  
Vol 67 (5) ◽  
pp. 845-853 ◽  
Author(s):  
A. Mallick ◽  
D. K. Tripathy ◽  
S. K. De
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Natural Rubber ◽  
Strain Amplitude ◽  
Polyacrylic Acid ◽  
Dynamic Mechanical Properties ◽  
Dynamic Strain ◽  
Thermally Induced ◽  
Dynamic Mechanical ◽  
Strain Dependent

Abstract Increases in dynamic strain amplitude (DSA) causes changes in the dynamic mechanical properties of high abrasion furnace (HAF) carbon black filled polyacrylic acid (PAA) and epoxidised natural rubber (ENR) blends. But the changes are more prominent in comparison to conventional rubber vulcanizates. It is believed that crosslinking between PAA and ENR in the presence of carbon black results in the formation of a network-induced-agglomerate superstructure which, however, breaks down on the application of dynamic strain.

Strain Dependence of Dynamic Mechanical Properties of Carbon Black-Filled Rubber Compounds

1996 ◽  
Vol 69 (1) ◽  
pp. 15-47 ◽  
Author(s):  
J. D. Ulmer
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Strain Amplitude ◽  
Dynamic Mechanical Properties ◽  
Model Description ◽  
Strain Dependence ◽  
Dynamic Mechanical ◽  
Filled Rubber ◽  
Rubber Compounds ◽  
Viscous Modulus

Abstract The strain dependencies of dynamic mechanical properties of carbon black-filled rubber compounds have been modeled by Kraus. Evaluation of the Kraus model with carbon black loadings up to 110 phr shows that it provides a fairly good overall description of elastic modulus, G′, as a function of strain, γ. The model description of G′ strain dependence improves with decreased carbon black loading, and is very good with carbon black loadings of 50 phr and less. The model description of viscous modulus strain dependence, G″(γ), is less successful than the G′(γ) description. Several empirical modifications of the viscous modulus model are examined. The most improved model is a very good approximation to viscous modulus over a wide experimental strain-range. Its utility, and that of the Kraus G′(γ) model, are illustrated through calculation of simple shear dynamic properties from torsion property measurements on a solid cylinder, where the strain amplitude varies across the specimen radius. The models allow transformation of the apparent moduli, reported as functions of strain amplitude at the cylinder's outer edge, to their true counterparts, G′(γ) and G″(γ), as functions of uniform strain amplitude. Although the G′(γ) and modified G″(γ) models apply to a wide range of experimental strains, some uncertainties associated with each model's accuracy remain, and there are inconsistencies in the relation of one model to the other. Reservations associated with the models might be resolved through refined treatments of the test specimen geometries.

The Dispersion of Carbon Black in Rubber Part III. The Effect of Dispersion Quality on the Dynamic Mechanical Properties of Filled Natural Rubber

1992 ◽  
Vol 65 (5) ◽  
pp. 1016-1041 ◽  
Author(s):  
A. Y. Coran ◽  
J-B. Donnet
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Natural Rubber ◽  
Shear Strain ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical ◽  
Short Period ◽  
Dispersion Quality ◽  
Carbon Black Dispersion

Abstract The Part I of this series described a rapid method for determining the quality of carbon-black dispersion. The second paper (Part II) was concerned with the kinetics of the dispersion of carbon black into natural rubber (dispersion quality as a function of mixing time) in an internal mixer. In this paper we consider the effects of changes in dispersion quality on the dynamic mechanical properties of both unvulcanized and vulcanized natural rubber. The effects of changes in the degree of carbon-black dispersion were measured by using a new prototype moving-die rheometer (which is presently being developed at Monsanto Instruments & Equipment Research Laboratory). By using this prototype rheometer, G′ and G″ were measured as functions of shear-strain amplitude, temperature, and frequency. Increases in the degree of carbon-black dispersion in uncured natural rubber (starting from very poor dispersion quality) give decreases in the values of both G′ and G″. The decrease in dynamic moduli with increases in the degree of carbon-black dispersion might be explained on the basis of a network of agglomerates which exists when the quality of dispersion is extremely poor. In the case of uncured samples, values of G′, measured at low strains (e.g. ±1%), become reduced after the imposition of a larger (±50%) sinusoidal shear strain for a short period of time (e.g. 3 s). Then, with the passage of time, the reduced value of G′ partially recovers. The extent of this recovery increases with increases in the dispersion rating DR. Similar results were obtained with respect to the loss modulus G″. In both cases, the extent of recovery is much less when the carbon black is very poorly dispersed. The unrecoverable proportion of G′ or G″ is also considered to be due to a network composed of mutually interactive agglomerates of carbon black.

Dynamic Mechanical Properties of a Carbon Black-Loaded Butyl Rubber Vulcanizate and a Carbon Black-Loaded Polyisobutylene

1982 ◽  
Vol 55 (5) ◽  
pp. 1403-1412 ◽  
Author(s):  
John D. Ferry ◽  
Edwin R. Fitzgerald
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Strain Amplitude ◽  
Dynamic Mechanical Properties ◽  
Butyl Rubber ◽  
Published Data ◽  
Dynamic Mechanical ◽  
Furnace Black ◽  
The Subject ◽  
Frequency Temperature

Abstract The dynamic mechanical properties of rubbers loaded with carbon black have been the subject of many investigations because of their importance in the performance of products, especially the energy dissipation, skid resistance, and other properties of vehicle tires. However, the important variables of frequency and temperature in oscillating deformations have usually been explored in fragmentary fashion. In particular, the degree to which these variables can be treated with frequency-temperature superposition appears to differ considerably depending on the type of compound investigated. In many cases, data have been insufficient to establish whether the essential criterion for superposition, namely, the same temperature dependence for all relaxation mechanisms, is satisfied. For this purpose, extensive measurements over wide ranges of closely spaced frequencies and temperatures are required. Such data are needed, in any case, to determine the responses of elements of a vehicle tire over the ranges of temperature and time scale to which they are subjected in use and to provide input information for thermo-mechanical modelling of power loss in tires. This paper is intended to be one of a series on dynamic mechanical properties of a variety of carbon black-loaded compounds over wide ranges of frequency and temperature. It describes results for a vulcanized butyl rubber loaded with a medium processing channel black, and the almost chemically identical linear polymer polyisobutylene loaded with a semireinforcing furnace black; these results are compared with previously published data for vulcanized butyl gum and pure polyisobutylene . The shear strain amplitude in these measurements is very small, of the order of 10−5 to 10−7, in a range of linear viscoelasticity as confirmed by sensitive tests, and thus the Mullins effect is avoided. The prominent dependence of viscoelastic properties on strain amplitude, as investigated by Payne and Watson and later workers, appears at considerably higher strains of 10−3 or more. Of course, the behavior in large deformations will be very different from that described here, but it is important to understand first the properties of the structure close to its equilibrium rest state.

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