A method for preparing branched polycarbonate by an interfacial polycondensation process and branched polycarbonate

Abstract

This invention belongs to the field of polycarbonate preparation technology, and particularly relates to a method for preparing branched polycarbonate by interfacial polycondensation and the branched polycarbonate. The method includes: mixing and reacting an aqueous phase containing a dihydroxy compound with an organic phase containing phosgene and a branching agent to obtain an oligomer reaction solution a, which does not contain unreacted phosgene; the absolute value of the difference in conversion rates between the branching agent and the dihydroxy compound is ≤10%; adding a capping agent and an alkaline solution to the oligomer reaction solution, and continuing the reaction until the conversion rate of the branching agent is ≥90%, and the hydroxyl content of the oligomer in the reaction solution is ≤2000ppm, to obtain a reaction solution b; adding a catalyst to the obtained reaction solution b, and continuing the reaction until the acyl chloride content in the reaction solution is ≤2ppm; the branched polycarbonate prepared by this invention does not contain gel components that are insoluble in good solvents, the total nitrogen content is 0-10ppm, and the hydroxyl content is 0-150ppm, both of which are at low levels, and the product will not exhibit defects such as crystal points in downstream applications.

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