Physical Aging, Plasticization and Their Effects on Gas Permeation in “Rigid” Polymers of Intrinsic Microporosity
Type
ArticleKAUST Department
Advanced Membranes and Porous Materials Research CenterChemical Engineering Program
Physical Science and Engineering (PSE) Division
Date
2015-08-29Online Publication Date
2015-08-29Print Publication Date
2015-09-22Permanent link to this record
http://hdl.handle.net/10754/576174
Metadata
Show full item recordAbstract
Long-term physical aging and plasticization, two mobility-based phenomena that are counterintuitive in the context of “rigid” polymers of intrinsic microporosity (PIMs), were evaluated using pure- and mixed-gas permeation data for representative ladder and semiladder PIMs. PIMs between 1 and 4 years old retained from 10- to 1000-fold higher H2 and O2 permeabilities than commercial membrane materials with similar or higher selectivities. A triptycene-based ladder polymer (TPIM-1) exhibited very large selectivity gains outweighing permeability losses after 780 days, resulting in unprecedented performance for O2/N2 (P(O2) = 61 Barrer, α(O2/N2) = 8.6) and H2/N2 (P(H2) = 1105 Barrer, α(H2/N2) = 156) separations. Interestingly, TPIM-1 aged more and faster than its more flexible counterpart, PIM-1, which exhibited P(O2) = 317 Barrer and α(O2/N2) = 5.0 at 1380 days. Additionally, the more “rigid” TPIM-1 plasticized more significantly than PIM-1 (i.e., TPIM-1 endured ∼93% increases in mixed-gas CH4 permeability over pure-gas values compared to ∼60% for PIM-1). A flexible 9,10-bridgehead (i.e., TPIM-2) mitigated the enhancements induced by physical aging but reduced plasticization. Importantly, intra-chain rigidity alone, without consideration of chain architecture and ultra-microporosity, is insufficient for designing aging- and plasticization-resistant gas separation membranes with high permeability and high selectivityCitation
Physical Aging, Plasticization and Their Effects on Gas Permeation in “Rigid” Polymers of Intrinsic Microporosity 2015:150829080103007 MacromoleculesPublisher
American Chemical Society (ACS)Journal
MacromoleculesAdditional Links
http://pubs.acs.org/doi/10.1021/acs.macromol.5b01581ae974a485f413a2113503eed53cd6c53
10.1021/acs.macromol.5b01581