Process for preparing aromatic polyimides and some polyimides prepared thereby



A process for preparing substantially completely cyclized aromatic polyimides, either monomeric, oligomeric or polymeric, is provided. The process involved the reaction of a mixture of at least one tetracarboxylic acid dianhydride, at least one aromatic diamine and an .alpha.,.beta.-carboxylic acid monoanhydride in at least one aromatic phenol, preferably cresols, in the presence of an organic azeotroping agent such as a cyclic hydrocarbon, preferably benzene, until substantially all of the water of reaction is eliminated. The monoanhydride provides reactive end groups which will enable the polyimide to cure by coupling together by addition or condensation thereby increasing molecular weight with little or no by-product. After the water is removed, it is preferred that the azeotroping agent be removed and then the polyimide increased in molecular weight by heating in the aromatic phenol. The polymer can then be isolated by concentration or precipitation as a powder, or the polymer in solution can be used to prepare coatings on various substrates.


Attribute NameValues
  • Process for preparing aromatic polyimides and some polyimides prepared thereby

Patent Number
  • US 4075171 B2

  • Gaetano Francis D'Alelio

Inventor From Local Institution
  • Gaetano Frank D'Alelio

Other Application
  • 05/533,468

  • 17

Classification (US Patent)
  • 528/170; 428/473.5; 528/171; 528/185; 528/188; 528/192; 528/220; 528/353; 544/337; 544/345; 548/423; 548/431; 548/433; 548/435;

Cooperative Patent Classification codes
  • C08G 73/101 (20130101); C08G 73/1057 (20130101); C08G 73/106 (20130101); C08G 73/1067 (20130101); C08G 73/1071 (20130101); C08G 73/1064 (20130101); Y10S 525/925 (20130101); Y10S 525/928 (20130101)

International Patent Classification codes
  • C08G 73/00 (20060101); C08G 73/10 (20060101); C08G 073/10 (); C08G 073/12 ()

  • eng

Date Issued
  • 1978-02-21

  • United States Patent and Trademark Office

  • University of Notre Dame Du Lac

Record Visibility Public
Content License
Departments and Units
Member of


Collections Featuring this Patent
Notre Dame Patents


Please Note: You may encounter a delay before a download begins. Large or infrequently accessed files can take several minutes to retrieve from our archival storage system.