Direct process for preparing semi-crystalline polyimides

摘要

The invention is a direct process for preparing semi- crystalline polyimides. This process comprises the steps of: providing a polar aprotic solvent, adding a dianhydride and a diamine to the solvent to form a mixture, stirring the mixture at ambient temperature, and adding glacial acetic acid to the mixture to provide a ratio of polar aprotic solvent to glacial acetic acid which ranges from about 90 to 10 to about 75 to 25 by volume to form a solution. The solution was heated to a range from about 110° C. to about 140° C. to form a polyimide precipitate. The polyimide precipitate was recovered as a semi- crystalline polyimide powder.