Study of thermal decomposition kinetics for polyimides based on 2,6-bis(4-aminophenyl)-4-(4-(4-aminophenoxy) phenyl) pyridine

This study reports on the preparation and thermal decomposition kinetics of a polyimide (PI) with phthalimide pendant (PI-1) and an analogous hyperbranched PI (PI-2). PI-1 was synthesized from 2,6-bis(4-aminophenyl)-4-(4-(4-aminophenoxy) phenyl) pyridine (BAAP) and 4,4'-(hexa-fluoroisopropylidene) diphthalic anhydride using a simple method with BAAP terminated by phthalic anhydride. The morphology of the PI structures was examined using X-ray diffraction. The thermal decomposition processes of the PIs were then studied according to a two-stage method using thermogravimetric analysis. The results indicated that both PIs exhibited excellent thermal stability, with a decomposition pattern of 5% mass loss beyond 508 degrees C and 10% beyond 529 degrees C. The two PIs exhibited similar levels of thermal stability in the first decomposition stage, but PI-1 exhibited higher stability in the second stage. The results indicate that PIs into which phthalimide pendants have been introduced retain their thermal stability in the first stage of decomposition and demonstrate enhanced thermal stability in the second stage.