To obtain an arom. polycarbonate with an increased mol.wt. without causing the degradation by dissolving a solid amorphous arom. precursor polycarbonate in a chlorinated hydrocarbon, removing insoluble matters from the soln., and adding thereto an org. nonsolvent to precipitate a solid purified polycarbonate.
The solid amorphous arom. precursor polycarbonate comprising structural units represented by the formula (wherein at least about 60% of R groups are org. arom. groups and the rest are aliph., alicyclic, or arom.) and having a wt. average mol.wt. of 5,000-300,000 is dissolved in a chlorinated hydrocarbon as the solvent at a temp. of 20-100°C to give an amorphous polycarbonate soln. The soln. is subjected to decantation, filtration, or centrifuge to be freed of insoluble matters and is treated with an alkanol soln. of a mineral acid to be decolored. Then, an org. solvent selected from among aliph. hydrocarbons, arom. hydrocarbons, hydroxyaliph. compds., aliph. ketones, and carboxylic esters is added to the soln. to precipitated a solid purified polycarbonate.
KING JOSEPH ANTHONY JR
BASUKAA BAARABUNAS IDIJI
SWAMINASAN SHIVARAM
BISHUNUU RAMCHANDORA RANADE
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