Organosoluble and thermally stable polyimides derived from a new diamine containing bulky-flexible triaryl pyridine pendent group

A novel kind of aromatic diamine, N-(4-(4-(2,6-diphenyl pyridine-4-yl) phenoxy) phenyl)-3,5-diaminobezamide (DPDAB), was synthesized via aromatic nucleophilic substitution of 3,5-dinitrobenzoylchloride with 4-(4-(2,6-diphenylpyridine-4-yl)phenoxy)aniline (DPPA), followed by palladium-catalyzed hydrazine reduction. This monomer was used to prepare polyimides (PIs) based on reaction with several commerically avaiable tetracarboxylic dianhydrides such as pyromellatic dianhydride (PMDA), benzophenone tetracarboxylic acide dianhydride (BTDA) and bicycle 2.2.2] oct-7-ene-2, 3,5,6-tetracarboxylic dianhydride (BCDA). These PIs had inherent viscosity in the range of 0.34–0.76 dL/g and showed good solubility in various aprotic polar solvents. The glass-transition tempratures (T _gs) of the PIs were in the range of 184–302°C, and showed high thermal stability with 10% weight loss in the temperature range of 360–500°C under nitrogen atmosphere.