Abstract: Polymeric compositions are described which result from blending a mixture comprising: (A) at least one amorphous polycarbonate; (B) at least one linear polycarbonate oligomer containing hydroquinone carbonate structural units; and (C) at least one polycarbonate formation catalyst.The polymeric compositions have particular application in the preparation of shaped articles for use in environments characterized by the presence of solvents, solvent vapors, and/or potential for fire conditions. Methods for increasing the solvent and flammability resistance of amorphous polycarbonates are also described.

Abstract: Blended polymer compositions are described which comprise: (A) at least one amorphous polycarbonate; and (B) at least one linear polycarbonate oligomer containing hydroquinone carbonate structural units.The blended polymer compositions having particular application in the preparation of shaped articles for use in environments characterized by the presence of solvents, solvent vapors, and/or potential for fire conditions. Methods for increasing the solvent and flammability resistance of amorphous polycarbonates are also described.

Abstract: The thermal stability of cyclic polycarbonate oligomers may be increased by reacting the oligomers with an effective amount of organic carboxylic or sulfonic acids.

Abstract: The molar concentration of chloroformate in an organic chloroformate solution is determined by adding an excess of a monohydroxyaromatic compound, water and a catalytic amount of a 4-dialkylaminopyridine such as 4-dimethylaminopyridine, titrating with aqueous base and taking as the end point the volume of base which achieves complete conversation of chloroformate groups to monoaromatic carbonate groups, as shown by a rapid rise in the pH of the aqueous phase of more than two points to a value in the range of 7-9. This method is particularly applicable to the determination of bischloroformate molar concentration in systems to be converted to cyclic polycarbonate oligomers. Conversion may be effected by condensation in the presence of a trialkylamine and aqueous base in the amount of about 3 moles per mole of bischloroformate.

Abstract: Cyclic copolycarbonate oligomer mixtures are prepared from mixtures of hydroquinone bischloroformate and bischloroformates of bisphenols, typically bisphenol A or a spirobiindane bisphenol, by condensation in the presence of an amine, an aqueous base and a non-polar organic liquid. By heating with a polycarbonate formation catalyst, they may be converted to solvent-resistant linear polycarbonates, many of which are crystalline.

Abstract: Bischloroformates of bisphenol compositions comprising hydroquinone or a hydroquinone-bisphenol A mixture are prepared by passing phosgene into a vigorously agitated mixture of water, an alkaline earth metal hydroxide, the bisphenols and a substantially inert, water-immiscible organic liquid such as methylene chloride. The molar ratio of water to alkaline earth metal hydroxide is in the range of about 3-8:1. The bisphenols and at least a portion of the organic liquid are preferably initially present in the reaction mixture, and the alkaline earth metal hydroxide is preferably added during phosgenation.

Abstract: Cyclic copolycarbonate oligomer mixtures are prepared from mixtures of hydroquinone bischloroformate and bischloroformates of bisphenols, typically bisphenol A or a spirobiindane bisphenol, by condensation in the presence of an amine, an aqueous base and a non-polar organic liquid. They may be converted to solvent-resistant linear polycarbonates, many of which are crystalline.