Abstract: A partially crosslinked polymer composition comprisinga) a polymer comprising from 25 to 95% by weight of polypropylene and from 5 to 75% by weight of a propylene copolymer with copolymerized C.sub.2 -C.sub.10 -alk-1-enes, the comonomer content being from 1 to 45% by weight, based on the total polymer,b) a random ethylene copolymer containing from 5 to 20% by weight of copolymerized C.sub.3 -C.sub.10 -alk-1-enes and having a density at room temperature of from 0.89 to 0.925 g/cm.sup.3, andc) an organosilane compound of the formula (I)A.sub.4-n SiR.sub.n (I)where A are identical or different acrylates or methacrylates or vinyl groups, R are identical or different C.sub.1 -C.sub.8 -alkoxy or C.sub.1 -C.sub.8 -acetoxy groups, and n is 1, 2 or 3,can be obtained by reacting a polymer mixture of the polymer a) and the random ethylene copolymer b) with the organosilane compound c) in the presence of a free-radical initiator and in the presence of a condensation catalyst at from 180.degree. to 280.degree. C.

Abstract: The present invention deals with a novel blowing agent masterbatch for the preparation of polystyrene foams, comprising:(a) 30 to 80 weight percent of a plasticizer-containing polystyrene having a Vicat softening temperature between 30.degree. and 50.degree. C.;(b) 20 to 70 weight percent of blowing agent based on solid organic acids and alkali metal (bi) carbonates; and optionally(c) 10 to 20 weight percent of cell regulators.