Analysis of governing factors controlling gas transport through fresh and aged triptycene-based polyimide films
Journal Article
·
· Journal of Membrane Science
- University of Notre Dame, IN (United States); DOE/OSTI
- University of Notre Dame, IN (United States)
- Commonwealth Scientific and Industrial Research Organization (CSIRO), Victoria (Australia)
- Chinese Academy of Sciences (CAS), Beijing (China)
In this report the fundamental gas transport properties and physical aging behavior of a series of triptycene-based polyimides with various substitution groups were investigated. Wide-angle x-ray diffraction revealed that the 6FDA-1,4-triptycene polyimides exhibit two chain packing domains with d-spacing values of ~6.7 Å and ~5.3 Å, corresponding to triptycene-induced chain packing disruption and chain segments lacking the triptycene moiety, respectively. Positron annihilation lifetime spectroscopy (PALS) showed a bimodal distribution of microcavity size made up of triptycene cleft cavities that are ~3 Å diameter and larger interchain cavities with an average diameter of ~7 Å. Additionally, PALS confirmed 6FDA-1,4-trip_CH3 has the lowest fractional free volume, primarily due to smaller contributions from the interchain cavities, and 6FDA-1,4-trip_CF3 has the largest fractional free volume. It was also found that the addition of substituent groups had a unique and positive effect on the aging properties over nine months, in which the addition of CH3 and CF3 groups led to permeability increases of ~20% and ~40%, respectively. This is caused by the combination of the lowered driving force for physical aging, the substituent groups sterically hindering tighter packing with time, and the interconnectivity and/or unblocking of free volume over time through small-scale, local chain motion.
- Research Organization:
- University of Notre Dame, IN (United States)
- Sponsoring Organization:
- ACS Petroleum Research Fund; Australian Research Council; USDOE; USDOE Office of Science (SC)
- Grant/Contract Number:
- SC0010330
- OSTI ID:
- 1534095
- Alternate ID(s):
- OSTI ID: 1397957
- Journal Information:
- Journal of Membrane Science, Journal Name: Journal of Membrane Science Journal Issue: C Vol. 522; ISSN 0376-7388
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Advanced gas separation membrane materials: rigid aromatic polyimides
Free volume manipulation of a 6FDA-HAB polyimide using a solid-state protection/deprotection strategy
Design, Synthesis and Characterization of Triptycene-Containing Macromolecules with Hierarchically Controlled Architectures as Functional Membrane Materials for Energy Applications
Conference
·
Sat Oct 01 00:00:00 EDT 1988
· Sep. Sci. Technol.; (United States)
·
OSTI ID:5995961
Free volume manipulation of a 6FDA-HAB polyimide using a solid-state protection/deprotection strategy
Journal Article
·
Fri Oct 09 20:00:00 EDT 2020
· Polymer
·
OSTI ID:1852807
Design, Synthesis and Characterization of Triptycene-Containing Macromolecules with Hierarchically Controlled Architectures as Functional Membrane Materials for Energy Applications
Technical Report
·
Tue Aug 27 00:00:00 EDT 2019
·
OSTI ID:1499993