Synthesis and Properties of Novel Triptycene-Based Polyimides

Two new triptycene-containing bis(ether amine)s, 1,4-bis(4-aminophenoxy)triptycene (4) and 1,4-bis(4-amino-2-trifluoromethylphenoxy)triptycene (6), were synthesized, respectively, from the nucleophilic chloro-displacement reactions of p-chloronitrobenzene and 2-chloro-5-nitrobenzotrifluoride with 1,4-dihydroxytriptycene in the presence of potassium carbonate, followed by palladium-catalyzed hydrazine reduction of the dinitro intermediates. The bis(ether amine) s were polymerized with six commercially available aromatic tetracarboxylic dianhydrides to obtain two series of novel triptycene-based polyimides 8a-f and 9a-f by using a conventional two-step synthetic method via thermal and chemical imidizations. All the resulting polyimides exhibited high enough molecular weights to permit the casting of flexible and strong films with good mechanical properties. Incorporation of trifluoromethyl groups in the polyimide backbones improves their solubility and decreases their dielectric constants. The fluorinated polyimides 9d and 9f derived from diamine 6 with 4,4'-oxydiphthalic anhydride and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), respectively, could afford almost colorless thin films. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 3109-3120, 2011