METHOD FOR RECOVERING POLYPHENYLENE OXIDES

摘要

A method for recovering polyphenylene oxide having a high bulk density and a reduced content of fine particles from a solution of a polyphenylene oxide, which comprises adding a non-solvent composed of a lower alkyl alcohol and water to an aromatic solvent solution of a polyphenylene oxide substantially free from impurities to precipitate the polyphenylene oxide, the weight ratio of the aromatic solvent to the lower alkyl alcohol being from 1:1 to 1:2 and the weight ratio of the lower alkyl alcohol to water being from 1:0.005 to 1:0.1 in the precipitation system, and the addition of the nonsolvent being controlled such that a liquid composition of the aromatic solvent, the lower alkyl alcohol and water forms a single phase; and recovering the precipitated polyphenylene oxide.