Interaction of a Polymer of Intrinsic Microporosity (PIM-1) with Penetrants

Abstract

Abstract:The characterisation, solubility testing, and alcohol adsorption studies of PIM-1 are reported. Techniques used for characterisation are N 2 sorption and ATR-FTIR analysis. A number of solvents were tested for their ability to dissolve low molecular weight (~30 000 gmol -1 ), medium molecular weight (~60 000 gmol -1 ), and high molecular weight (~120 000 gmol -1 ) PIM-1.Results showed solubility of PIM-1 in these solvents to be dependent on molar mass. CHCl 3 , tetrahydrofuran (THF), CH 2 Cl 2 , dicholobenzene (DCB), 1,2,4-trichlorobenzene (TCB), and acetophenone were found to be good solvents at all molecular weights. Treatment of PIM-1 with nonsolvents, namely: small alcohols and water, followed by solvent removal, caused swelling, resulting in an increase in BET surface area of about 11 %, except for water, which reduced BET surface area by the same amount (11 %). Methanol (MeOH) treatment resulted in a new population of micropores around 0.6 nm. The change after ethanol (EtOH) and propanol (PrOH) treatment was not as significant. Hydrogen bonding between alcohols and PIM-1 was also investigated using shifts in the frequencies of FTIR peaks for the ether and the nitrile functional groups. Nitrile group frequencies for the alcohols were consistently blue-shifted, whereas the ether frequencies were red shifted. Both red-and blue-shifts were used as a measure of hydrogen bond strength.

Thin film composite membranes based on a polymer of intrinsic microporosity derived from Tröger's base: A combined experimental and computational investigation of the role of residual casting solvent

“…Consequently, we consider also the value for  of polymer acceptable. The results indicated that both CHCl3 and DCM are good solvents for PIM-EA(H2)-TB (as for PIM-1 [50]), however, the polymer usually shows better interaction with CHCl3.…”

“…In general, the casting solvent also has an important role in determining the free volume morphology of the membrane, exerting a key influence on the gas transport (e.g., sorption, diffusion and permeation) [16]. The solvent properties may influence the final microstructure of a glassy polymer matrix via interaction with the polymer macromolecules, such as dipole-dipole interactions and hydrogen bonding [17][18][19][20]. PIMs, like other highly permeable polymers, tend to retain a considerable amount of casting solvent.…”

The Effect of Thermal Treatment on the Hydrogen‐Storage Properties of PIM‐1

“…The pore size distributions, shown in Figure C, were calculated using the Horvath‐Kawazoe method, which associates the average interaction energy in the pore to the relative pressure required to fill a specific micropore diameter. From Figure C, it is clear that while all samples show microporosity (pores <20 Å), sample 1 has more of the larger micropores in the pore size distribution with a mean pore size centred at 6.6 Å, similar to the literature for PIM‐1 . With increasing annealing temperature and time, the PIM‐1 samples have a smaller proportion of micropores, suggesting annealing at higher temperature and time enhanced the ultramicroporosity (pores <10 Å).…”

“…BET surface areas were calculated by applying the Brunauer Emmett Teller (BET) model within the pressure range recommended by Rouquerol et al . The values shown in Table are in agreement with the literature . The highest apparent BET surface area was obtained for samples 2 and 3.…”

Composite membranes based on geometrically constrained PIM-1 for dehumidification of gas mixtures

“…It is well documented that the soaking of microporous polymers in methanol and ethanol can be considered as one of the ways to rejuvenate the polymer permeance [24,25]. The specific interactions of alcohol molecules with polymer chains leads to the enhancement of local segmental mobility of the macromolecules and the most pronounced effect is observed when methanol is used.…”