| abstract |
This disclosure is concerned with a single step process for the production of diphenol terminated polycarbonates by the transesterification of diphenols, bis-aryl carbonates and polymeric diols with aliphatically bound terminal hydroxyl groups. These diols are selected from polyesters, polyethers, polythioethers and polyacetals. The transesterification is carried out at elevated temperatures under vacuum optionally in the presence of a catalyst with the ratios of the reactants being such as to avoid the retention of any terminal aliphatic hydroxyl groups or aryl carbonate groups. |