Enhancement of CO₂ Affinity in a Polymer of Intrinsic Microporosity by Amine Modification

Abstract

Nitrile groups in the polymer of intrinsic microporosity PIM-1 were reduced to primary amines using borane complexes. In adsorption experiments, the novel amine–PIM-1 showed higher CO2 uptake and higher CO2/N2 sorption selectivity than the parent polymer, with very evident dual-mode sorption behavior. In gas permeation with six light gases, the individual contributions of solubility and diffusion to the overall permeability was determined via time-lag analysis. The high CO2 affinity drastically restricts diffusion at low pressures and lowers CO2 permeability compared to the parent PIM-1. Furthermore, the size-sieving properties of the polymer are increased, which can be attributed to a higher stiffness of the system arising from hydrogen bonding of the amine groups. Thus, for the H2/CO2 gas pair, whereas PIM-1 favors CO2, amine–PIM-1 shows permselectivity toward H2, breaking the Robeson 2008 upper bound.

Tailoring Physical Aging in Super Glassy Polymers with Functionalized Porous Aromatic Frameworks for CO2 Capture

“…The preferential CO 2 transport in these membranes could be attributed to the enhanced affinity between the polar functional moieties and CO 2 molecules, similar to those observed in functionalized polymer membranes. 21,22 PAF-1-Li 6 C 60 incorporation enhanced CO 2 permeabilities in PTMSP membranes by 85 %, the largest enhancement observed in the present article. PTMSP/PAF-1-Li 6 C 60 films tested periodically exhibited selective-aging properties where H 2 , N 2 , and CH 4 permeabilities were reduced by 20 -40 % over 365 days, while maintaining CO 2 permeability.…”

Facile conversion of nitrile to amide on polymers of intrinsic microporosity (PIM-1)

“…The increase in the hydrophilicity had also been noted by other PIM-1 post-synthesis modification work. For example, the water contact angle of the base-hydrolyzed PIM-1 and amine-PIM-1 were found to be 60 and 66 , respectively [12,20].…”

“…As summarized in Scheme 1, the most popular target for post-synthesis modification of PIM-1 is the nitrile group, which has been converted to carboxylic acid [7], tetrazole [8], methyl tetrazole [9], amidoxime [10], thioamide [11], amine [12] and hydroxyalkylaminoalkylamide [13]. Many significant results have been reported by some of these post-modified PIMs.…”

“…As demonstrated in the tetrazole-PIMs [8], amine-PIM-1 [12], ethanolamine-PIMs [13], and amidoxime-PIM-1 [10], the presence of lone pair electron containing nitrogen group within polymer backbone can enhance interaction with CO 2 and thus improve its solubility and uptake. Upon our survey for post-synthesis modification work, we noticed that amide-containing PIM has never been specifically reported.…”

Imide-linked microporous organic framework polymers for CO2 adsorption

“…The significance of the subnanometer porosity and nitrogen-rich content within the framework structure of MOPs represent key factors in gas storage and separation applications, as demonstrated by the promising results of the recently reported nanoporous polymers containing N-functionalities. 17,22,23 Therefore, their outstanding properties in terms of chemical nature and porosity are anticipated to have a substantial influence in enhancing the CO 2 uptake capacity. Accordingly, the adsorption behaviour of CO 2 and its uptake capacity on the prepared PIM-OFPs were investigated over different temperatures (273, 295 and 323 K) at both 1 and 35 bar in order to reflect the industrial conditions.…”