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Thermally Rearranged Polymer Membranes Containing Tröger's Base Units Have Exceptional Performance for Air Separations |
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| Authors: | Stephen M Meckler Dr Jonathan E Bachman Benjamin P Robertson Chenhui Zhu Prof Jeffrey R Long Dr Brett A Helms |
| Institution: | 1. The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA;2. Department of Chemistry, The University of California, Berkeley, Berkeley, CA, USA;3. Department of Chemical and Biomolecular Engineering, The University of California, Berkeley, Berkeley, CA, USA;4. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA;5. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA |
| Abstract: | The influence of segmental chain motion on the gas separation performance of thermally rearranged (TR) polymer membranes is established for TR polybenzoxazoles featuring Tröger's base (TB) monomer subunits as exceptionally rigid sites of contortion along the polymer backbone. These polymers are accessed from solution‐processable ortho‐acetate functionalized polyimides, which are readily synthesized as high‐molecular‐weight polymers for membrane casting. We find that thermal rearrangement leads to a small increase in d‐spacing between polymer chains and a dramatic pore‐network reconfiguration that increases both membrane permeability and O2/N2 selectivity, putting its performance above the 2015 upper bound. |
| Keywords: | gas separations membranes polymers selective transport Trö ger's base |