Fabrication and characterization of novel hyperbranched polyimides with excellent organosolubility, thermal and mechanical properties

A series of amine-terminated and anhydride-terminated hyperbranched polyimides (HBPIs) were successfully prepared with various commercial dianhydrides and a novel BB′ 2 -type aromatic triamine, 2,4,6-tris[4-(4-aminophenoxy)phenyl]pyridine, with a symmetrical triaryl-substituted pyridine segment and prolonged flexible linkages. The chemical structure of the triamine monomer and the hyperbranched structure of the resulting polymers were verified by Fourier transform infrared spectroscopy and 1 H-NMR spectroscopy. The resulting HBPIs, which mainly held an amorphous morphology, exhibited improved organosolubilities in several strong polar aprotic solvents, good heat resistance with glass-transition temperature values in the range 218.6–311.0°C, and excellent thermal stabilities in both N 2 and air [the temperature at 5% weight loss ( T 5% ) in N 2 was higher than 529.8°C and the T 5% in air was higher than 465.1°C]. The obtained HBPI films also showed outstanding mechanical properties with tensile strength, tensile modulus, and elongation at break values of 86.4–101.3 MPa, 1.73–2.04 GPa, and 5.07–10.67%, respectively; considerable optical transparency; low water absorption; and neutral interface wettability. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41544.