GB965457A - Chain terminated polycarbonates - Google Patents

Abstract

Linear polycarbonates are chain-terminated by reaction with a monofunctional alcohol, mercaptan or silanol, the silanol being formed in situ by the hydrolysis of a monohalosilane. The polycarbonates are made by dissolving a diol in aqueous sodium hydroxide, adding an organic solvent for the polycarbonate resin, passing phosgene into the reaction mixture, adding up to 0.01 mole of the chain-terminator per mole of diol, and then agitating the reaction mixture until the polymerization is complete. A further portion of diol may be added to the partial reaction product of the diol and the phosgene. The chain-terminators may have the formula: (a) R-X-H where R is a hydrocarbon radical free of aliphatic unsaturation (e.g. alkyl, cycloalkyl or aralkyl) and X is oxygen and sulphur and is attached to an aliphatic or cycloaliphatic carbon atom; (b) <FORM:0965457/C3/1> where R is a hydrocarbon radical free of aliphatic unsaturation (e.g. alkyl, cycloalkyl or aryl), each R1 is an alkyl radical and n is 1-3; (c) <FORM:0965457/C3/2> where R is an alkylene or cycloalkylene group containing 2-9 carbon atoms and each R1 is hydrogen or an alkyl radical containing 1-4 carbon atoms; (d) H-(CF2CF2)n-CH2OH where n is 1-8; (e) <FORM:0965457/C3/3> where X is chlorine, bromine or iodine and each R is a hydrocarbon radical containing 1-16 carbon atoms (e.g. alkyl, cycloalkyl, phenyl or alkylphenyl). Preferred diols are bis-phenols of formula: <FORM:0965457/C3/4> where B is alkylene, alkylidene, aralkylene, oxygen or sulphonyl and each R is hydrogen, alkyl, cycloalkyl, aryl or halogen. The polycarbonate forming reaction is preferably effected in the presence of quaternary ammonium compound as catalyst. Examples describe the manufacture of chain-terminated bisphenol-A polycarbonates. The polycarbonate may be used in the manufacture of films, fibres, tubes, rod, bottle caps, gears, laminates and coating compositions.