Synthesis and Performance of 6FDA-Based Polyimide-Ionenes and Composites with Ionic Liquids as Gas Separation Membranes

• Published in: Membranes (Basel) Vol. 9; no. 7; p. 79
• Main Authors: O’Harra, Kathryn E., Kammakakam, Irshad, Devriese, Emily M., Noll, Danielle M., Bara, Jason E., Jackson, Enrique M.
• Format: Journal Article
• Language: English
• Published: Marshall Space Flight Center MDPI 03.07.2019; MDPI AG
• Subjects: 6FDA polyimides; BASIC BIOLOGICAL SCIENCES; Carbon dioxide; CO2 Separation; Composite materials; Gas separation; Gases; Hybrid Membranes; Hybrids; Inorganic, Organic And Physical Chemistry; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Ionenes; Ionic liquids; Membranes; Permeability; Polymers; Thermal stability; United States > US; Ionenes; Co2 Separation; Hybrid Membranes; 6fda Polyimides; CO2 Separation; ionenes; 6FDA polyimides
• ISSN: 2077-0375; 2077-0375
• DOI: 10.3390/membranes9070079

Three new isomeric 6FDA-based polyimide-ionenes, with imidazolium moieties and varying regiochemistry (para-, meta-, and ortho- connectivity), and composites with three different ionic liquids (ILs) have been developed as gas separation membranes. The structural-property relationships and gas separation behaviors of the newly developed 6FDA polyimide-ionene + IL composites have been extensively studied. All the 6FDA-based polyimide-ionenes exhibited good compatibility with the ILs and produced homogeneous hybrid membranes with the high thermal stability of ~380 °C. Particularly, [6FDA I4A pXy][Tf2N] ionene + IL hybrids having [C4mim][Tf2N] and [Bnmim][Tf2N] ILs offered mechanically stable matrixes with high CO2 affinity. The permeability of CO2 was increased by factors of 2 and 3 for C4mim and Bnmim hybrids (2.15 to 6.32 barrers), respectively, compared to the neat [6FDA I4A pXy][Tf2N] without sacrificing their permselectivity for CO2/CH4 and CO2/N2 gas pairs.