(514g) Polybenzimidazole-Derived Asymmetric Carbon Molecular Sieve Hollow Fiber Membranes for Gas Separations

Polymer carbonization is an attractive approach to fabricate carbon molecular sieve (CMS) materials with tailored pore structure for superior gas perm-selectivities than that achieved using traditional polymer membrane materials. The polymer precursor properties, including their molecular structure and inter- and intra-molecular chain packing characteristics ultimately drive the separation characteristics of the resultant polymer-derived CMS membranes post-pyrolysis. Owing to their highly rigid and rod-like chain configurations, and exceptional thermo-chemical characteristics, polybenzimidazole (PBI) materials are ideal precursors for obtaining the CMS membranes. Herein, we report development and characterization of asymmetric polybenzimdiazole-derived CMS hollow fiber membranes (HFMs) having morphology tailored for the desired gas separation performances. Together with programmable carbonization protocols, PBI precursor HFMs having tailored morphology endowed the resulting CMS HFMs with controlled macro- and microporosity leading to exceptional H₂/CO₂ and O₂/N₂ permselective characteristics. Comprehensive investigations of the fabrication protocols for the PBI-CMS HFMs and influence of the operating conditions on the gas separation performance will be discussed.