A free radical suspension polymerization process for obtaining crosslinked styrene butadiene ternary copolymers which comprises the polymerization of styrene monomers, butadiene monomers, and crosslinking components in the presence of a surfactant, a stabilizer, and a first and second initiator; and wherein the aforementioned components are present in an aqueous phase; heating the resulting aqueous mixture at a temperature of from about 50.degree. C. to about 110.degree. C.; thereafter heating the mixture at a temperature of from about 110.degree. C. to about 150.degree. C.; followed by cooling and isolating the desired product.