Abstract: A process for producing foamed articles containing thermoplastic aromatic polycarbonates is disclosed. Accordingly, thermoplastic aromatic polycarbonates are mixed with about 0.01 to 10% by weight of Al.sub.2 O.sub.3 (H.sub.2 O).sub.3 and the mixture is either extruded in an extruder at temperatures from 220.degree. C. to 320.degree. C. without application of a vacuum to produce foamed molded articles or it is injection molded in injection molding machines without application of vacuum at temperatures from 290.degree. C. to 330.degree. C. to produce molded foam articles.

Abstract: A process for the production of polycarbonate foam moldings is disclosed. Accordingly, a composition is prepared comprising mixing a thermoplastic polycarbonate resin and 0.01 to 1 mole-% of a transesterification catalyst anda) 0.1 to 5 mole-% of an aromatic polycarboxylic acid, optionally along with about 0.1 to 5 mole-% of at least one member selected from the group consisting of aliphatic hydroxy carboxylic acids and aliphatic polyalcohols, orb) 0.1 to 5 mole-% of H.sub.2 O, optionally along with at about 0.1 to 5 mole-% of at least one member selected from the group consisting of aliphatic hydroxycarboxylic acids and an aliphatic alcohols, orc) the additives of said a) and b), ord) 0.1 to 5 mole-% of at least one member selected from the group consisting of diarylcarbonates and oligocarbonates,said percent based in every case on moles aromatic carbonate structural units ##STR1## in which --O--R--O is a diphenolate residue.