Strain-Dependent Dynamic Properties of Carbon-Black Reinforced Vulcanizates. II. Elastomer Blends

Abstract The three-dimensional aggregated structure of carbon black in elastomer blends behaves in a similar fashion to that of the individual elastomers. The elastomer seems to act merely as a dispersing medium. The properties of the rubber reflect the structural effects of the filler superimposed upon the elastomer itself. The elastomer molecules no doubt retain their individual characteristics of rotation of bonds which govern the stiffness of the molecule. However, the superimposed carbon-black network exerts the predominant effect, as far as the low-strain dynamic characteristics are concerned. The polymeric medium seems to influence this interaction by determining the magnitude of agglomeration and distribution of black in the phases, but does not have visible influence on the overall characteristics of the carbon-black networks. In this respect blends of two elastomers behave as a single elastomer. The importance of the present work is that the strain-dependent dynamic properties of blends of elastomers are very similar to those of single elastomers. In tires and antivibration applications, the strain imposed is usually less than 10%. More and more blends of elastomers are being used for these applications. The filler structure and its breakdown at these strains have an important contribution to hardness, modulus, and hysteresis of these compounds.