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A direct process for preparing semi-crystalline polyimidesThe 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.
Document ID
19950013991
Acquisition Source
Legacy CDMS
Document Type
Other - Patent Application
Authors
Chang, Alice C. (Lockheed Engineering and Sciences Co. Hampton, VA., United States)
St.clair, Terry L. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 16, 2013
Publication Date
September 1, 1994
Subject Category
Nonmetallic Materials
Report/Patent Number
NAS 1.71:LAR-15020-1
Patent Number: NASA-CASE-LAR-15020-1
Report Number: NAS 1.71:LAR-15020-1
Patent Application Number: US-PATENT-APPL-SN-299385
Accession Number
95N20407
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Patent
NASA-CASE-LAR-15020-1
Patent Application
US-PATENT-APPL-SN-299385

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