Poly(alkenyl substituted aromatic) and elastomer containing polymer compositions and process for their preparation

Poly(alkenyl substituted aromatic) containing polymer compositions, obtained by a process comprising:

• (a) reacting a polyphenylene ether or a structurally related polymer thereof of the formula ##STR6## wherein R.sub.1 and R.sub.4 each may represent hydrogen, halogen, a phenyl group, alkenyl group, alkadienyl group, an aryloxy group, or wherein R.sub.1 and R.sub.4 each may represent an alkyl group or an alkoxy group, each of the latter containing 12 or less carbon atoms and each optionally substituted by halogen, cyano, hydroxy, phenyl or amino, whereas alkyl or alkoxy groups attached to the terminal phenol nucleus of the chain may be substituted by an amino, dialkylamino or a di(alkanoyl) amide group, wherein the alkyl groups each contain 4 or less carbon atoms, wherein R.sub.2 and R.sub.3 each may represent hydrogen, halogen, a phenyl group, alkenyl group, alkadienyl group, aryloxy group or wherein R.sub.2 and R.sub.3 each may represent a primary or secondary alkyl group or alkoxy group as defined for R.sub.1 and R.sub.4, optionally substituted by halogen, cyano, hydroxy, phenyl, and wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 may represent different or the same groups in one repeating unit, and n represents an integer having a value of at least 50 and more preferably 100 to 500, with an acid halide, an acid anhydride or ketene, in at least one alkenyl substituted aromatic monomer, the amount of polyphenylene ether or structurally related polymer in the reaction mixture being in the range of from 5 to 30% by weight calculated on the complete final composition;
• (b) dissolving at least one ethylenepropylenediene monomer (EPDM) rubber having a specific density in the range of from 0.85 to 0.95, a Mooney viscosity (ML(1+4) 125.degree. C.) in the range of from 30 to 80, an ethylene content in the range of from 50 to 70% by weight, in the reaction mixture of step (a) in an amount of from 5 to 20% by weight together with a diblock copolymer A--B which is optionally partially hydrogenated, optionally mixed with minor amounts of triblock copolymers A--B--A, wherein A represents a poly(alkenyl aromatic) block and B represents an optionally, partially hydrogenated poly (conjugated diene) block, having a number average molecular weight in the range of from 10,000 to 1,000,000 and showing a glass transition temperature of -20.degree. C. or below, said diblock copolymer being added to the reaction mixture of step (a) in an amount of from 1 to 5% by weight calculated on the weight of the complete final composition;
• (c) prepolymerizing the obtained mixture until a prepolymerized mass is formed having a degree of polymerization of from 5 to 20%;
• (d) suspending the resulting prepolymerized mass in an aqueous medium;
• and
• (e) polymerizing by thermal initiation or by means of at least one free radical initiator, optionally in the presence of an expanding agent, the prepolymerized mass of step (d).