Synthesis of high Tg and organosoluble poly(N-arylene benzimidazole ether imide) copolymers by C-N/C-O coupling reaction

A series of poly(N-arylene benzimidazole ether imide) copolymers PEIBIs were prepared from 1H,3H-5,5-bis-benzimidazole, bisphenol-A and 4,4-bis(4-fluorophthalimido)diphenyl ether by nucleophilic displacement polymerization. The resulting copolymers PEIBI(10-90) demonstrated moderate to good solubility in polar aprotic solvents and high glass transition temperatures (T(g)s) of 228-336 degrees C, good thermal stability with 10% weight loss temperatures in the range of 503-548 degrees C. All copolymer films showed good mechanical properties with tensile strengths of 101-130 MPa, tensile moduli of 3.3-4.0 GPa, elongations at break of 5-7%, and also presented low water uptake (0.15-0.34%). The wide-angle X-ray diffraction results revealed the amorphous nature of copolymers. The copolymer PEIBI-80 showed good balance in solubility, thermal and mechanical properties.