Optically active and organosoluble poly(amide-imide)s derived fromN,N′-(Pyromellitoyl)bis-l-histidine and various diamines: Synthesis and characterization

Novel polypyrrolones containing fluorenyl groups in the main chain: Synthesis and characterization

A novel aromatic tetraamine, 2′,7′-bis(3,4-diaminophenoxy)-spiro(fluorene-9,9′- xanthene), was synthesized, which was employed to react with various commercial available aromatic dianhydrides to yield a series of polypyrrolones (PPys). The intermediate poly(amide amino acid) had inherent viscosities of 0.28–0.35 g/dl and could be thermally converted into lightly yellow PPys films. All the resulting PPys exhibited good thermal stabilities. The glass-transition temperatures were in the range of 371–386°C, and the temperatures of 5 and 10% weight loss were 472–549°C and 552–612°C in nitrogen, respectively; the residual weight was above 62% at 800°C. In addition, the PPys films had tensile strengths in the range of 42.3–85.8 MPa, tensile moduli of 1.8–2.5 GPa, and elongations at break of 6.8–7.4%. The polymer films also exhibited excellent alkaline hydrolysis resistance, retaining their original shapes and toughness after boiling for 7 days in 10% sodium hydroxide solution.