Abstract: The present invention relates to a composition for producing a thermoplastic molding compound containing A) at least one aromatic polycarbonate and/or aromatic polyester carbonate containing at least 500 ppmw of phenolic OH groups, wherein the weight-average molecular weight Mw of component A determined by gel permeation chromatography at room temperature in dichloromethane as solvent using a polycarbonate calibration standard is in the range from 15 000 to 40 000 g/mol, B) at least one copolymer containing structural units derived from methyl methacrylate and 0.

Abstract: The present invention relates to a method for producing a thermoplastic moulding compound containing A) at least one aromatic polycarbonate and B) an additional polymer that is chemically different from polymer A and that contains at least one type of functional group selected from ester groups, epoxy groups, hydroxyl groups, carboxyl groups and carboxylic anhydride groups, comprising the steps of a) melting and thoroughly mixing the components A and B in the presence of a catalyst according to component Cat a temperature in the range of from 200° C. to 350° C. and b) solidifying the composition by cooling the composition, the component A having an average molecular weight Mw of at least 3000 g/mol, characterised in that, in the method step a), at least one part of the component A is reacted with the component B to form a copolymer, and the catalyst C being a specific phosphonium salt.