Synthesis and characterization of polycarbonates by melt phase interchange reactions of alkylene and arylene diacetates with alkylene and arylene diphenyl dicarbonates.

This work presents a new synthetic approach to aromatic and aliphatic polycarbonates by melt polycondensation of bisphenol A diacetates with alkylene- and arylenediphenyl dicarbonates. The diphenyl dicarbonates were prepared from phenyl chloroformate and the corresponding dihydroxy compounds. The process involved a precondensation step under a slow stream of dry argon with the elimination of phenyl acetate, followed by melt polycondensation at high temperature and under vacuum. The potential of this reaction is demonstrated by the successful synthesis of a series of aromatic-aromatic and aromatic-aliphatic polycarbonates having inherent viscosities from 0.19 to 0.43 dL/g. Thus low to intermediate molecular mass polymers were obtained. The (13)C-NMR spectra of the carbon of the carbonate group showed that the formed polycarbonates contain partial random sequence distribution of monomer residues in their chains. The polycarbonates were characterized by inherent viscosity, FTIR, (1)H-NMR and (13)C-NMR spectroscopy. The glass transition temperatures, measured by DSC, of the polycarbonates were in the range 13-108 degrees C. The thermogravimetric curves of showed that these polymers have good thermal stability up to 250 degrees C. The present approach may open the door for novel polycarbonates containing other organic functional groups.