GB927178A - Improvements in or relating to polymeric materials - Google Patents

Abstract

New polymers, which contain thiocarbonate linkages, are made by reacting a dihydric phenol with thiophosgene, a diester of thiocarbonic acid or a bis chlorothiocarbonate of a dihydric phenol. Copolymers, which also contain carbonate linkages, may be made (a) by reacting the dihydric phenol with a mixture of an ester-forming derivative of thiocarbonic acid and the corresponding oxygen analogue; (b) by reacting a low molecular weight polythiocarbonate with an ester-forming derivative of carbonic acid in admixture with a dihydric phenol; or (c) by reacting a low molecular weight polycarbonate with an ester-forming derivative of thiocarbonic acid in admixture with a dihydric phenol. The dihydric phenol may be 4:41-dihydroxydiphenyl sulphone, 2:6-dihydroxynaphthalene or 4:4-dihydroxydiphenyl ether but is preferably a bis-phenol of formula <FORM:0927178/IV(a)/1> where R1 and R2 are hydrogen atoms, or alkyl, aryl or aralkyl groups, and X, X1, Y and Y1 are hydrogen atoms or halogen atoms or alkyl groups. Reaction with the thiophosgene or the bis-chlorothiocarbonates is preferably effected in the presence of aqueous alkali, methylene chloride and, possibly, sodium dithionite, triethylamine or phenol; the polymer being p precipitated from solution in methylene chloride with acetone. Reaction with the diester of thiocarbonic acid may be effected in the presence of titanium butoxide. The polymers are soluble in methylene chloride, benzene and dioxane and are useful in the manufacture of photographic film bases (see Group XX) and fibres.