Abstract: Graft copolymers (P1) having an average particle size of from 40 to 2000 nm contain at least (P1.1) a soft segment having a glass transition temperature of not more than 10.degree. C. as a grafting base, which segment contains at least one acrylate as the monomer or as one of two or more monomers copolymerizable with one another, and at least one crosslinking agent, and (P1.2) a hard segment having a glass transition temperature of at least 11.degree. C. as a graft layer, which segment contains at least one vinylaromatic monomer as one of two or more monomers copolymerizable with one another, that region of the subsequent graft layer which is adjacent to the grafting base P1.1 comprising at least one vinylaromatic monomer and the region facing away from the grafting base comprising at least one vinylaromatic monomer with at least one monomer copolymerizable therewith, and blends and thermoplastic materials contain these graft copolymers.

Abstract: This invention relates to flame retardant blends of polysulfone, with polyalkylene phthalate. The present blends are flame retardant, even at thin part thickness.