Polycarbonate synthesis by the melt phase carbonate‐ester interchange reaction of bisphenol‐A diacetate with dimethyl carbonate

Abstract

Abstract The molecular weight of polycarbonate formed by the carbonate‐ester interchange reaction of bisphenol‐A diacetate (BPAC 2 ) and dimethyl carbonate (DMC) was found to depend on the composition of the oligomer formed in its first stage. At a [DMC] : [BPAC 2 ] ratio of 2, an oligomer with relatively higher acetate end group concentration was formed. This upon further polycondensation yielded a polycarbonate of inherent viscosity, 0.2‐0.25 dL/g. Upon addition of DMC at a later stage in the oligomer‐forming reaction, an oligomer containing relatively higher carbonate end groups could be obtained. These oligomers gave polycarbonates higher inherent viscosity, 0.4‐0.5 dL/g. It is therefore proposed that oligomers having carbonate end groups are more reactive in self‐polycondensation than those containing acetate end groups. © 1995 John Wiley & Sons, Inc.