Organosoluble Co-Polynaphthalimides Based on 1,4,5,8-Naphthalene Tetracarboxylic Dianhydride, 9,9-Bis(4-aminophenyl) Fluorene and Various Bis(ether amine)s

A series of novel co-polynaphthalimides were synthesized from 1,4,5,8-naphthalene tetracarboxylic dianhydride, 9,9-bis(4-aminophenyl) fluorene and various bis(ether amine)s by high-temperature solution polycondensation reaction. The synthesized polymers were characterized using FTIR and elemental analysis techniques. As a result, all polymers were soluble in m -cresol and some of them were dissolved in 1‑methyl-2-pyrrolidone. In addition, these polymers could afford transparent and tough films with strength at break of 77–100 MPa via casting relative m -cresol solutions. These polymers are characterized by softening temperatures of 230–267°C, also they exhibited high thermal stability with 10% weight loss temperatures above 500°C in nitrogen or air atmosphere, and higher 44% of char yields at 800°C.