Abstract: A two step solvent-free process for the preparation of polycarbonates having a low degree of branching is disclosed. Accordingly, the process comprise(i) transesterifying in the melt, at temperatures of from 80.degree. to 250.degree. C. and under atmospheric pressure and for a time of up to five hours of diphenols and carbonic acid diaryl esters in the presence of a catalyst to form an oligocarbonate having a weight average molecular weight of from 8,000 to 18,000 and an OH-end group content of from 25 to 50%, and(ii) polycondensing of said oligocarbonate at temperatures of from 250.degree. C. to 295.degree. C. and pressures of from <500 mbar to 0. 01 mbar,said catalyst being present in an amount of 10.sup.-1 to 10.sup.-8 tool of a catalyst per tool of diphenol, said catalyst being at least one member selected from the group consisting of quaternary ammonium compounds and quaternary phosphonium compounds.

Abstract: The present invention relates to a process for isolating polycarbonates in which a solution of polycarbonate in an organic solvent is dispersed with steam and which is characterized in that the resulting suspension of polycarbonate particles, condensed water and water/solvent vapor is subsequently dried in a tube with cross-sectional constrictions.

Abstract: The object of the present invention is to provide a process for the preparation of aromatic polycarbonates in the molten state using fluoride catalysts.

Abstract: An improvement to the continuous process for the production of polycarbonates by interphase polycondensation is described. Accordingly, the organic phase and the aqueous phase are combined in a tube, forming chlorocarbonic acid ester and further alkali hydroxide is added at, or shortly after, the maximum concentration of said ester is reached. The resulting emulsion is then changed to an oil-in-water emulsion which is then separated and worked up in known manner.

Abstract: The invention relates to flame-proof polyamide materials which can be processed by a thermoplastic method and consist of blends of amorphous, partly aromatic polyamides and 3-40% by weight of polyphosphonates.

Abstract: Extrusion of solutions of aromatic polyesters and aromatic polyphosphonates gives copolyphosphonates with improved notched impact strength.

Abstract: Polyester-phosphonates, polycarbonatophosphonates and polyester-carbonatophosphonates having improved impact strength and notched impact strength as compared with melt-condensation products can be prepared in such a way that, in the first stage, oligophosphonates with hydroxyl end groups are prepared by melt-transesterification and melt-condensation and these are subjected in a second stage to a phase boundary process.

Abstract: The invention relates to a process for the preparation of polyphosphonic acid amides by condensation of 0.5-2 moles of a phosphonic acid diaryl ester and 1 mole of an aliphatic, aromatic, araliphatic or heterocyclic primary or secondary diamine in the melt at 50.degree.-350.degree. C., if appropriate in the presence of a catalyst which accelerates the condensation and under an inert gas atmosphere, the corresponding phenol being split off.

Abstract: This invention relates to flame resistant moulding compounds produced from mixtures of styrene polymers halogenated organic compounds, special polyphosphonic acid amides and optionally conventional additives.

Abstract: Thermotropic aromatic polyesters with high rigidity and favorable melt viscosity contain condensed radicals of (a) p-hydroxybenzoic acid, (b) hydroquinone and/or 4,4'-dihydroxydiphenyl, (c) isophthalic acid and optionally terephthalic acid and (d) benzophenone dicarboxylic acid in defined weight ratios.