Abstract: A process for the preparation of expandable granules based on polyaryl ether sulfones and/or polyether imides, containing from 5 to 20% by weight of a physical blowing agent, the blowing agent and the polymers being mixed in an extruder and subsequently extruded directly into a medium at less than 40.degree. C., and a process for the production of foams from expandable granules based on polyaryl ether sulfones and/or polyether imides, containing from 5 to 20% by weight of a physical blowing agent, the granules being press molded at from 120.degree. to 250.degree. C. and at a pressure of from 5 to 30 bar to form a sheet, and the sheet being subsequently foamed by reducing the pressure, are described.

Abstract: Foams of density 0.1 to 1.0 g/cm.sup.3 based on aromatic polyether ketones and other thermoplastic polymers having a high melting point are obtained by melting an intimate mixture of the polymer and from 0.5 to 10% by weight of an aliphatic or aromatic dicarboxylic acid or polycarboxylic acid which suffers a weight loss of 50% or more with elimination of gaseous decomposition products on heating to from 130 to 300.degree. C., and simultaneously cooling and molding the melt.

Abstract: Expandable polymers in particle form for the preparation of foams having high heat distortion resistance contain from 20 to 94.9% by weight of a styrene polymer, from 0.1 to 75% by weight of a polyphenylene ether and from 5 to 20% by weight of a blowing agent mixture of aliphatic or cycloaliphatic hydrocarbons on the one hand and aromatic hydrocarbons, alcohols, ketones, ethers, esters and/or chlorohydrocarbons on the other hand.

Abstract: Particulate expandable styrene polymers containing organic halogen compounds and, to improve processability, from 0.0001 to 1.0% by weight, based on the styrene polymer, of an amine which is soluble in styrene and free from hydroxyl groups.

Abstract: Particulate, expandable styrene polymers containing a flame-proofing organic halo compound as expanding agent and also a mixture of from 2.5 to 30% by weight of a hydrocarbon of from 3 to 6 carbon atoms and from 97.5 to 70% by weight of monofluorotrichloromethane, based on the total weight of said mixture serving as expanding agent, show good processability and exhibit self-extinguishing properties even during processing.