Three novel fluorinated polyimides (PIs) were synthesized via one‐step solution polycondensation from a new diamine monomer, 4‐(3‐methoxy‐4‐(difluoromethoxy)phenyl)‐2,6‐bis(4‐aminophenyl)pyridine, and three commercially available aromatic dianhydrides. The solubility, thermal, optical, hydrophobic and gas transport properties of the obtained PIs were investigated. The results demonstrated that these polymers present good solubility in dimethylformamide, N‐methylpyrrolidone, dimethylsulfoxide, dimethylacrylamide, CHCl3, tetrahydrofuran and CH2Cl2 at room temperature or upon heating. Meanwhile, they displayed excellent thermal properties with glass transition temperature of 261–345 °C, weight loss temperatures at 10% of 518–523 °C as well as char yield of 60–62% at 800 °C in nitrogen atmosphere. Furthermore, the PI membranes have good hydrophobic properties with water contact angle value in the range 90.1–92.0°. Moreover, they show excellent optical properties, with cut‐off wavelength (λcut‐off) values of 368–381 nm and wavelength values at 80% transmittance (λ80%) of 421–462 nm. The pure gas permeabilities of He, CO2, O2 and N2 of the PI membranes were measured by the method of constant volume–variable pressure. The PI containing 4,4′‐(hexafluoroisopropyl)diphthalic anhydride moiety exhibits the largest molecular chain spacing and free volume, giving the best gas transport performance in this work. Molecular simulation results show that the introduction of fluorine‐containing structure and bulky pendant into polymer backbones is beneficial for gas transport. © 2023 Society of Industrial Chemistry.

In this study, a novel fluorinated diamine monomer 2,2-bis(4-(4-aminophenylsulfonyl)phenyl)hexafluoropropane (BASA) was designed and synthesized. Then a series of polyimides were obtained via one-pot high-temperature polycondensation of BASA with commercial aromatic...

No abstract

No abstract

Through one-step copolymerization of 4-(4-[1-morpholinyl]phenyl)-2,6-bis (4-aminophenyl)pyridine (MPAP), 9,9-bis(4-aminophenyl)fluorene (BAFL), and (4,4 0 -hexafluoroisopropylidene)diphthalic anhydride (6FDA), a series of polyimides containing morpholine group, pyridine ring, fluorene "cardo" pendant and hexafluoroisopropyl group are obtained. The synthesized polyimides have good thermal stability, high transparency, outstanding hydrophobicity and excellent solubility in not only high-boiling solvents but also low boilingpoint solvents. Furthermore, polyimide films have large molecular chain spacing, which is consistent with the free volume calculated by molecular simulation. Consequently, polyimide membranes display better gas permeability values of CO 2 (up to 24.47 Barrer) and He (up to 45.04 Barrer), and good ideal gas selectivity values of CO 2 /N 2 (up to 15.33 Barrer) and He/N 2 (up to 23.89 Barrer), which also shows potential application of polyimide matrix materials in gas separation.