(397b) Engineering of Carbon Molecular Sieve Hollow Fibers Derived from 6FDA-Based Polyimides for Propylene/Propane Separation

Separation of propylene from propane is an industrially important yet challenging process due to the close size difference and similar physical properties between propylene and propane. Carbon molecular sieve (CMS) membranes offer extraordinary combinations of scalable economical processability and excellent separation performance, making them appealing for propylene/propane separation. In this talk, we will present key structure features in 6FDA-based polyimide precursors (kinked backbone and crosslinkable structures) to yield advanced CMS membranes for propylene/propane separation. Beyond that, optimized actual asymmetric CMS hollow fibers using crosslinkable 6FDA-based polyimide precursors were developed. The effects of processing conditions including pre-crosslinking at temperatures below and above Tg of polyimide precursor, VTMS treatment and final pyrolysis temperatures on morphology and propylene/propane separation performance of CMS hollow fibers will be discussed. Our work shows synergistic benefits of molecularly engineering polyimide precursors and optimizing pyrolysis conditions to produce high performance CMS hollow fibers to push the state of the art for challenging propylene/propane separation.