TY - JOUR
T1 - Structural evolution and gas separation properties of thermally rearranged polybenzoxazole (TR-PBO), polymer-carbon transition (PCT) and early-stage carbon (ESC) membranes derived from a 6FDA-hydroxyl-functionalized Tröger's base polyimide
AU - Yerzhankyzy, Ainur
AU - Wang, Yingge
AU - Xu, Feng
AU - Hu, Xiaofan
AU - Ghanem, Bader
AU - Ma, Xiaohua
AU - Balcik, Marcel
AU - Wehbe, Nimer
AU - Han, Yu
AU - Pinnau, Ingo
N1 - KAUST Repository Item: Exported on 2023-06-01
Acknowledged KAUST grant number(s): BAS/1/1323-01-01, BAS/1/1372-01-01
Acknowledgements: This research was supported by funding (BAS/1/1323-01-01) and (BAS/1/1372-01-01) from King Abdullah University of Science and Technology.
PY - 2023/5/29
Y1 - 2023/5/29
N2 - The changes in physical, chemical, and gas permeation properties of a heat-treated hydroxyl-functionalized Tröger's base-derived intrinsically microporous polyimide, 6FDA-HTB, were systematically studied. Polyimide samples were heated-treated for 30 minutes at a fixed temperature to form (i) polybenzoxazole (PBO) by thermal rearrangement (TR) from ∼420 to ∼440 °C, (ii) polymer-carbon transition (PCT) from ∼460 to ∼500 °C, and (iii) early-stage carbon (ESC) membranes from >500 to 600 °C. As frequently observed in previous studies, TR-derived PBO membranes showed an increase in gas permeability with a concomitant decrease in gas-pair selectivity. The intermediate PCT region represents a transition state from a pure PBO to a partially carbonized polymer with superior properties by showing a simultaneous boost in gas permeability and gas-pair selectivity. The ESC membranes formed between 550 to 600 °C possessed further enhanced selectivity but reduced permeability due to tightening of the amorphous CMS structure. The mixed-gas separation properties of selected aged samples, pristine 6FDA-HTB, PBO (6FDA-HTB-420), intermediate PCT (6FDA-HTB-480), and early stage CMS analogs (6FDA-HTB-550 and 600), were investigated using a 1:1 CO2/CH4 feed up to 30 bar. In this series, early-stage CMS membranes displayed the best mixed-gas CO2/CH4 separation properties with performance significantly surpassing the 2018 polymer mixed-gas upper bound.
AB - The changes in physical, chemical, and gas permeation properties of a heat-treated hydroxyl-functionalized Tröger's base-derived intrinsically microporous polyimide, 6FDA-HTB, were systematically studied. Polyimide samples were heated-treated for 30 minutes at a fixed temperature to form (i) polybenzoxazole (PBO) by thermal rearrangement (TR) from ∼420 to ∼440 °C, (ii) polymer-carbon transition (PCT) from ∼460 to ∼500 °C, and (iii) early-stage carbon (ESC) membranes from >500 to 600 °C. As frequently observed in previous studies, TR-derived PBO membranes showed an increase in gas permeability with a concomitant decrease in gas-pair selectivity. The intermediate PCT region represents a transition state from a pure PBO to a partially carbonized polymer with superior properties by showing a simultaneous boost in gas permeability and gas-pair selectivity. The ESC membranes formed between 550 to 600 °C possessed further enhanced selectivity but reduced permeability due to tightening of the amorphous CMS structure. The mixed-gas separation properties of selected aged samples, pristine 6FDA-HTB, PBO (6FDA-HTB-420), intermediate PCT (6FDA-HTB-480), and early stage CMS analogs (6FDA-HTB-550 and 600), were investigated using a 1:1 CO2/CH4 feed up to 30 bar. In this series, early-stage CMS membranes displayed the best mixed-gas CO2/CH4 separation properties with performance significantly surpassing the 2018 polymer mixed-gas upper bound.
UR - http://hdl.handle.net/10754/692277
UR - https://linkinghub.elsevier.com/retrieve/pii/S0376738823004209
U2 - 10.1016/j.memsci.2023.121764
DO - 10.1016/j.memsci.2023.121764
M3 - Article
SN - 0376-7388
SP - 121764
JO - Journal of Membrane Science
JF - Journal of Membrane Science
ER -