Process for manufacture of polymer compositions containing a polyvinylarene and EPDM rubber.

A process for the manufacture of polymer com­ positions containing a polyvinylarene and EPDM rub­ ber, which process comprises: (a) dissolving in at least one vinylarene monomer of from 8 to 20% by weight, and preferably from 9 to 18% by weight, relative to the final composi­ tion, of at least one EPDM rubber, optionally mixed with a linear (hydrogenated) conjugated diene-vinylarene block copolymer, said block copolymer having a number average molecular weight in the range of from 10,000 to 1,000,000; (b) prepolymerizing the obtained solution until a polymerization degree of from 0.01 to 25%; (c) suspending the prepolymerized mass into an aqueous medium which contains at least one sus­ pending agent; and (d) suspension polymerizing until substantially complete monomer conversion is obtained, op­ tionally in the presence of an expanding agent, and polymer compositions so obtained