Synthesis of cardo containing asymmetric poly(ether‐naphthalimide‐phthalimide)s

Abstract A series of cardo based asymmetric polyimides containing bulky rigid naphthalimide and phthalimide groups were prepared from asymmetric monomer bishaloimide and bisphenols by solution polycondensation. Bishalo(naphthalimide‐phthalimide) monomers containing different terminal leaving groups (Cl, F, NO 2 ) were synthesized, and the reactivity difference of these monomers was compared for the successful synthesis of polyimides. The inherent viscosities of the polyimides were in the range 0.51 − 0.60 dL g −1 in N ‐methyl‐2‐pyrrolidone at 30 °C. These polyimides demonstrated good organosolubility and mechanical properties with tensile strengths of 93 − 120 MPa, tensile moduli of 3.5 − 5.3 GPa and elongations at break of 2.8% − 4.3%. The polyimides showed high glass transition temperatures ( T g ) ranging from 330 to 363 °C. The 10% weight loss ( T 10% ) of asymmetric polyimides reached 436 − 500 °C in nitrogen and 417 − 476 °C in air. The water uptake of the polyimides was in the range 0.35% − 0.72%. © 2017 Society of Chemical Industry