Highly CO2-Selective Gas Separation Membranes Based on Segmented Copolymers of Poly(Ethylene oxide) Reinforced with Pentiptycene-Containing Polyimide Hard Segments

作者：Luo Shuangjiang; Stevens Kevin A; Park Jae Sung; Moon Joshua D; Liu Qiang; Freeman Benny D; Guet Ruilan^*

来源：ACS Applied Materials & Interfaces, 2016, 8(3): 2306-2317.

DOI：10.1021/acsami.5b11355

• CO2-selective gas separation membrane
• poly(ethylene oxide)
• pentiptycene
• segmented copolymer

Poly(ethylene oxide) (PEO)-containing polymer membranes are attractive for CO2-related gas separations due to their high selectivity toward CO,. However, the development of PEO-rich membranes is frequently challenged by weak mechanical properties and a high crystallization tendency of PEO that hinders gas transport. Here we report a new series of highly CO2-selective, amorphous PEO-containing segmented copolymers prepared from commercial Jeffamine polyetheramines and pentiptycene-based polyimide. The copolymers are much more mechanically robust than the non-pentiptycene containing counterparts due to the molecular reinforcement mechanism of supramolecular chain threading and interlocking interactions induced by the pentiptycene structures, which also effectively suppresses PEO crystallization leading to a completely amorphous structure even at 60% PEO weight content. Membrane transport properties are sensitively affected by both PEO weight content and PEO chain length. A nonlinear correlation between CO, permeability with PEO weight content was observed due to the competition between solubility and diffusivity contributions, whereby the copolymers change from being size-selective to solubility-selective when PEO content reaches 40%. CO, selectivities over H-2 and N-2 increase monotonically with both PEO content and chain length, indicating strong CO2-philicity of the copolymers. The copolymer film with the longest PEO sequence (PEO2000) and highest PEO weight content (60%) showed a measured CO2 pure gas permeability of 39 Barrer, and ideal CO2/H-2 and CO2/N-2 selectivities of 4.1 and 46, respectively, at 35 degrees C and 3 atm, making them attractive for hydrogen purification and carbon capture.

• 出版日期2016-1-27