Abstract: This invention relates to processable ionic elastomer compositions having improved compression set properties, especially at elevated temperatures. In this invention an intractable ionic elastomer, for example, a sulfonated elastomer is blended with from 10 to 70 parts per hundred of a crystalline polyolefin to yield novel compositions having the above properties. Preferably the ionic elastomer is a sulfonated ethylene propylene terpolymer having from about 0.2 to 20 mole percent sulfonate groups, at least 95% of which are combined with counterions selected from the group consisting of Groups IA, IIA, IB, and IIB of the Periodic Table of Elements, aluminum, antimony, lead, and mixtures thereof. The sulfonated polymer is combined with said counterions by neutralization of a polysulfonic acid precurser with a basic material in which the desired counterion is present as the cation thereof.

Abstract: This invention relates to blends of sulfonated elastomers with crystalline polyolefins. The sulfonated elastomer comprises from about 0.2 to about 20 mole percent sulfonate groups, at least 95% of which are combined with metal counter ions selected from the group consisting of Groups I and II of the Periodic Table of the Elements, aluminum, and lead; organic amines; and mixtures thereof. The crystalline polyolefin is preferably selected from the group consisting of polyethylene, including high and low density polyethylenes, and polypropylene. The crystalline polyolefin comprises a minor portion of said blends.