Synthesis and characterization of polyimides based on new fluorinated 3,3′-diaminobiphenyls

✍ Scribed by Brian C. Auman; Tanya L. Myers; David P. Higley

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 190 KB
• Volume: 35
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19970915)35:12<2441::aid-pola14>3.0.co;2-7

✦ Synopsis

Two new fluorinated diamine monomers, 3,3-diamino-5,5-bis(trifluoromethyl)biphenyl and 3,3 -diamino-6,6-bis(trifluoromethoxy)biphenyl, as well as a known nonfluorinated analog, 3,3 -diaminobiphenyl, were synthesized. Reaction of these diamines with rigid, highly rod-like dianhydrides produced poly(amic acid)s and polyimides, which were spin coated and thermally treated to produce polyimide films for evaluation in electronics applications. It was hoped that these polyimide films would exhibit an ideal combination of low thermal expansion, reduced water absorption, and low dielectric constant but with improved elongation due to the ''crankshaft'' nature of the 3,3 -biphenyl unit. Unlike polyimide films from analogous 4,4 -diaminobiphenyls, however, the 3,3 -diaminobiphenyl-based polyimides did not yield low in-plane thermal expansion coefficient in spin-coated films. In some cases high elongation was achieved, but with high thermal expansion. These new diamines may nevertheless find utility in polyimides and polyaramides for membrane, fiber, and other applications. Additionally, they may be useful in modifying the properties of polymer backbones via copolymerization.