12.5 IMMISCIBLE ELASTOMER BLENDS 12.5.1 Formation
immiscible blends can be made from any two dissimilar elastomers. They can be made by in situ copolymerization, blending polymer solutions or suspensions and mechanical mixing. These procedures have been reviewed by Mangaraj(2002) and Corish and Powell(1974). In contrast to blends of other polymers elastomers can be either"preblended" or"phase mixed" with each other(CoEish and Powell, 1974). "Preblended" systems are those where the compounding ingredients(e.g., fillers, plasticizers, and curatives) are added simultaneously to a mixture of the immiscible polymers. In"phase mixed" blends, ingredients are added separately to each ofthe individual polymers in separate compounding operations. The compounded elastomers are then blended together. Phase mixed blends provide a greater certainty of the initial interphase location of fillers plasticizers, and curatives than the preblends