Role of intrachain rigidity in the plasticization of intrinsically microporous triptycene-based polyimide membranes in mixed-Gas CO2/CH4 separations
KAUST DepartmentAdvanced Membranes and Porous Materials Research Center
Chemical Engineering Program
Physical Science and Engineering (PSE) Division
Online Publication Date2014-10-22
Print Publication Date2014-11-11
Permanent link to this recordhttp://hdl.handle.net/10754/563851
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AbstractBased on high-pressure pure- and mixed-gas (50:50) CO2/CH4 separation properties of two intrinsically microporous triptycene-based polyimides (TPDA-TMPD and TPDA-6FpDA), the intrachain rigidity central to "conventional PIM" design principles is not a singular solution to intrinsic plasticization resistance. Despite the significant intrachain rigidity in TPDA-TMPD, a 300% increase in PMIX(CH4), 50% decrease in α(CO2/CH4) from 24 to 12, and continuous increase in PMIX(CO2) occurred from 4 to 30 bar. On the other hand, the more flexible and densely packed TPDA-6FpDA exhibited a slight upturn in PMIX(CO2) at 20 bar similar to a dense cellulose acetate (CA) film, also reported here, despite a 4-fold higher CO2 sorption capacity. Microstructural investigations suggest that the interconnected O2- and H2-sieving ultramicroporosity of TPDA-TMPD is more sensitive to slight CO2-induced dilations and is the physical basis for a more extensive and accelerated plasticization. Interchain rigidity, potentially by interchain interactions, is emphasized and may be facilitated by intrachain mobility.
CitationSwaidan, R., Ghanem, B., Al-Saeedi, M., Litwiller, E., & Pinnau, I. (2014). Role of Intrachain Rigidity in the Plasticization of Intrinsically Microporous Triptycene-Based Polyimide Membranes in Mixed-Gas CO2/CH4 Separations. Macromolecules, 47(21), 7453–7462. doi:10.1021/ma501798v
SponsorsThe authors acknowledge financial support of this work by KAUST funding for Prof. Ingo Pinnau.
PublisherAmerican Chemical Society (ACS)