| 摘要 |
Polyesters are made by reacting (a) an organic dicarboxylic acid or anhydride with (b) a vicinal alkylene oxide containing three or four carbon atoms and having attached to a carbon atom of the oxirane ring a methyl or ethyl group substituted by two or more fluorine, chlorine or bromine atoms, in the presence of a catalyst which is a reaction product of aluminium isopropoxide and a carboxylic acid. The catalyst may be added as such or formed in situ. Up to 50% by weight of the alkylene oxide may be replaced by a second vicinal alkylene oxide which is saturated and which on either or both of the carbon atoms of the oxirane ring, is unsubstituted or is substituted by one or two alkyl and/or alkoxy groups having 1 or 2 carbon atoms and in which one of the alkyl or alkoxy groups may be substituted by one halogen atom. The dicarboxylic acid may be malonic, succinic, perfluorosuccinic, glutaric, perfluoroglutaric, adipic, perfluoroadipic, pimelic, suberic, azeloic, sebacic, tetrahydrophthalic, hexahydrophthalic, chlorendic, phthalic, isophthalic, terephthalic, maleic, fumaric, chloromaleic, itaconic, citraconic or mesaconic. Monocarboxylic acids may also be included in the reaction mixture. The polyesters derived from unsaturated dicarboxylic acids may be copolymerized with unsaturated monomers, e.g. styrene, butyl methacrylate, triallyl isocyanurate or diallyl phthalate. A suitable polymerization catalyst is benzoyl peroxide, with or without dimethyl phosphite. |
