I. INTRODUCTION

Blends of elastomers are of technological and commercial importance since they allow the user to access properties of the final blended and vulcanized elastomer that are not accessible from a single, commercially available elastomer alone. These potentially improved properties include chemical, physical, and processing benefits. In reality, all blends show compositionally correlated changes in all of these properties compared to the blend components. The technology of elastomer blends is largely focused on the choice of individual elastomers and the creation of the blends to achieve a set of final properties. This chapter shows some of the instances of the uses of elastomer blends. Empirical guidelines for the creation of novel blends of elastomers is a comparatively more difficult proposition.

Blends provide an acceptable technological process for accessing properties not available in a single elastomer. In elastomers composed of a single monomer in a single insertion mode (e.g., 1,2 polybutadiene), there are no other procedures available except blends. In the case of elastomers that are copolymers (e.g., styrene butadiene rubber [SBR]), changes in intramolecular composition, such as formation of a block polymer instead of random copolymer at the same composition, are effective. However, intramolecular changes are limited by available synthesis processes. Intermolecular changes, in either composition or distribution of monomers, such as in blends, are not limited by such systemic or synthetic limitations.

Theoretically, blends of elastomers can attain a wide variation in properties. Combinations of elastomers can lead to changes in properties...