Highly soluble fluorinated polyimides with promising gas transport performance and optical transparency

Abstract

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...

Synthesis of colorless polyimides derived from benzimidazole diamines with bis‐amide structures

“…However, the introduction of CF 3 or CH 3 side groups contributed to limiting the tight packing of molecular chains. The stacking density of molecular chains was reduced so the diffusion and dissolution of molecular solvents were facilitated 36 . So as shown in Table 2, PI1 and PI2 could easily dissolve in commonly used high boiling solvents (NMP, DMAc, DMSO, DMF) without stirring or heating, which was better than our previous copolymer obtained by polymerization with HPMDA but without these side groups in diamines 32 …”

“…This result can be explained in two ways. First, the bulky N ‐phenyl pendant, CH 3 or CF 3 side groups had highly stereoscopic hindrance, which could disturb the self‐chain alignment, resulting in loose chain packaging and aggregation 31,35,36 . Second, these substituent groups were in a twisted structure, which was also adverse to the chain packaging and aggregation 35 .…”

“…First, the bulky N-phenyl pendant, CH 3 or CF 3 side groups had highly stereoscopic hindrance, which could disturb the self-chain alignment, resulting in loose chain packaging and aggregation. 31,35,36 Second, these substituent groups were in a twisted structure, which was also adverse to the chain packaging and aggregation. 35 The d-spacing of PI1 was smaller than PI2, indicating the CH 3 side group was smaller than CF 3 and had less influence in chain packaging and F I G U R E 1 1 H NMR spectra of 4a and 5a.…”