Conference paper
A high free-volume pentiptycene-based polyimide for Co2 removal
2017 AIChE Annual Meeting, pp.1017-1026
Oct 2017
Abstract
The widespread use of gas-separation processes in the chemical and petrochemical industries has motivated many to search for gas-separation processes more efficient than conventional processes. Gas separation using polymeric membranes has emerged as a more cost effective, less energy demanding, and more environmentally friendly alternative [1]. Among polymers used in membrane fabrication, polyimides (PIs) exhibit good chemical, mechanical, and thermal stability as well as excellent processability and solubility in different solvents [2]. However, common polyimides have low free volume (just between 10-20%), as explained by Robeson's upper bound and Freeman's theory [3, 4]. The incorporation of a rigid moiety into the PI backbone was found to lead to highly permeable and selective PIs, known as polymers of intrinsic microporosity (PIM)-PI. Pentiptycene is a highly rigid moiety from iptycene family consisting of five benzene rings forming an H-shaped core block. The bulky structure of pentiptycene impedes chain packing and provides large molecular space between arene rings. Furthermore, pentiptycene's open clefts endow pentiptycene-based membrane with high internal free volume equivalent to the kinetic diameter of light gases [5]. However, the presence of two etheric oxygens in the backbone of pentiptycene-based membranes causes chain packing, resulting in a decrease in regularity and free volume [6]. So far, all pentiptycene-based PI membranes synthesized from pentiptycene diamines have shown low permeability but high selectivity due to their lower free volume. A range of 0.171-0.197 has been reported for the fraction free volume of pentiptycene-based membranes.
In this paper, for the first time we report the synthesis and characterization of a pentiptycene-based dianhydride (PPDAn) and a pentiptycene imide-containing diamine (PPImDA). Two novel pentiptycene-based PIs [PPDAn-Durene and PPImDA-4, 4′-hexafluoroisopropylidene diphthalic anhydride (6FDA)] are synthesized using the high temperature one-step imidization reaction. PPImDA-6FDA shows high molecular weight and excellent solubility in common organic solvents, and has an extraordinarily high free volume of 0.233 (confirmed by XRD patterns) due to the presence of −C (CF3)2− units, the rigid durene, and the pentiptycene moiety in the polymer structure. Finally, gas transport properties of PPImDA-6FDA (in CO2 removal from natural and flue gas streams) are investigated and compared to those of 6FDA-durene. The high free volume of PPImDA-6FDA points to the great potential of this polymer for CO2 removal.
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Details
- Title
- A high free-volume pentiptycene-based polyimide for Co2 removal
- Creators
- Ahmad A. Shamsabadi - Drexel UniversityFarzad Seidi - Vidyasirimedhi Institute of Science and TechnologyMohammad Nozari - Drexel UniversityMasoud Soroush - Drexel University, Chemical and Biological Engineering
- Publication Details
- 2017 AIChE Annual Meeting, pp.1017-1026
- Conference
- 2017 AIChE Annual Meeting (Minneapolis, Minnesota, United States, 29 Oct 2017–03 Nov 2017)
- Publisher
- AIChE
- Number of pages
- 10
- Resource Type
- Conference paper
- Language
- English
- Academic Unit
- Chemical and Biological Engineering
- Identifiers
- 991022005883904721