Effect of thermal processing on brominated 6FDA-DAM for effective propylene/propane separation

• Published in: Separation and purification technology 2021-05, Vol.262, p.118331, Article 118331
• Main Authors: Do, Xuan Huy, Nguyen, Que Thi, Kim, Sejin, Lee, Albert S., Baek, Kyung-Youl
• Format: Article
• Language: English
• Subjects: Gas separation membrane; Microporous organic membrane; Propylene/propane separations; Thermal cross-linking
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2021.118331

[Display omitted] •Effect of treatment temperature on crosslinkable 6FDA-DAM membrane was examined.•Cross-linking and microporosity were optimized for propylene/propane separations.•Cross-linking increases the plasticization resistance of membranes. Developing polymeric membranes with propylene/propane separation performance surpassing the upper bound has been received much attention. Herein, a highly controlled thermal treatment process yielding microporous polyimide membranes made from dense brominated-polyimide membrane precursor via thermal debromination/cross-linking approach is demonstrated. We showed that facile thermal treatment could generate a narrow size distribution of micro-voids as well as covalent linkages between inter/intra polymer chains while the polyimide backbone structure remained intact. The thermally treated membranes were well-characterized by FTIR, TGA, WAXD, solid-state 13C NMR and N2 adsorption/desorption isotherm. Single gas propylene/propane (C3H6/C3H8) separation performance greatly improved in terms of both selectivity and permeability, surpassing the trade-off line while maintaining flexible membrane properties. A thermal cross-linking treatment at 380 °C for 5 h exhibited the best C3H6 permeability of 84.70 barrer and C3H6/C3H8 selectivity of 14.6 with high plasticization resistance.