Synthesis of an o-Cresolphthalein-Based Polyimide and Its Derivative Cross-Linked Thermally Rearranged Polymers for Gas Separation

• DOI: 10.1021/acs.macromol.4c02958
• Publication Date: 2025-01-02T08:03:26Z
• Authors: Zhongzheng Ren; Guoke Zhao; Fuwei Wang; Bo Chen; Gongqing Tang; Yiqun Liu; Pei Li
• Keywords: Phenolphthalein; Quinoxaline

Phenolphthalein-based polyimides and their derivative cross-linked thermally rearranged polymers (XTR) exhibited attractive gas transport properties. This study attempted to further improve the performance of XTR by tuning molecular structures a phenolphthalein-based diamine, diamino-phenolphthalein (DAP). We synthesized an o-cresolphthalein-based diamine (OCA), which had similar structure DAP except that there were two methyl groups on ortho position hydroxyl DAP. The OCA monomer reacted with 4,4′-(hexafluoroisopropyl)phthalic anhydride (6FDA) form polyimide, 6FDA-OCA, was used as precursor heating in argon. Molecular simulation results indicated gave 6FDA-OCA backbone lower torsion angle higher rotation energy than 6FDA-DAP. led Tg, better performance, plasticizing resistance After TR reactions, CO2 permeability 6FDA-OCA-450 reached 3743 Barrer, 60% 6FDA-DAP-450, ideal selectivity CO2/CH4 18.8, slightly 18.6 Therefore, strategy introducing benzene ring phenolphthalein successful enhance properties polymers.