Influence of methanol conditioning and physical aging on carbon spin-lattice relaxation times of poly(1-trimethylsilyl-1-propyne)

171

The derived MMM were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and single gas permeation tests. Gas permeation measurements showed that MMM incorporated with modified and non-modified CNTs exhibited different gas separation performance. The f-MWCNT MMM show better performance compared to MMM with non-modified CNTs in terms of dispersion and permeability at 2 wt% f-MWCNTs loading without sacrificing selectivity. According to diffusivity and solubility data derived from the time-lag method, the PEG chains on MWCNTs show interaction with CO 2 as indicated by an increase of the solubility of the polar gas and a reduction of the solubility of non-polar gas, which is advantageous for CO 2 /N 2 separation. The mechanical properties and experimental sorption isotherms of CO 2 and N 2 of the f-MWCNTs/PIM MMM were enhanced as well. KeywordsMixed matrix membrane, Multi-walled carbon nanotubes, Polymer of intrinsic microporosity 1 1. Introduction:

Section: Mixed Matrix Membrane Preparationmentioning

confidence: 99%

Enhanced gas permeability by fabricating mixed matrix membranes of functionalized multiwalled carbon nanotubes and polymers of intrinsic microporosity (PIM)

Khan

Filiz

Bengtson

et al. 2013

171

“…After solvent evaporation, the resulting films were delaminated and conditioned by soaking in methanol for approximately 50 min. Immersing the membranes in methanol reverses prior film formation history, in a manner similar to protocols previously developed for microporous polyacetylenes and PIM-1 [27,28]. After leaving the films under ambient atmospheric conditions for 1 h, the films were dried in a vacuum oven at 100 • C for 2 days.…”

Section: Pim-1 and Silica Nanoparticles Filled-pim-1 Membranes Preparmentioning

confidence: 99%

Gas transport behavior of mixed-matrix membranes composed of silica nanoparticles in a polymer of intrinsic microporosity (PIM-1)

Ahn

Chung

Pinnau

et al. 2010

254

189

Gas transport behavior of mixed-matrix membranes composed of silica nanoparticles in a polymer of intrinsic microporosity (PIM-1) Ahn, Juhyeon; Chung, Wook-Jin; Pinnau, Ingo; Song, Jingshe; Du, Naiying; Robertson, Gilles P.; Guiver, Michael D.This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Recently, high-free volume, glassy ladder-type polymers, referred to as polymers of intrinsic microporosity (PIM), have been developed and their reported gas transport performance exceeded the Robeson upper bound trade-off for O 2 /N 2 and CO 2 /CH 4 . The present work reports the gas transport behavior of PIM-1/silica nanocomposite membranes. The changes in free volume, as well as the presence and volume of the void cavities, were investigated by analyzing the density, thermal stability, and nano-structural morphology. The enhancement in gas permeability (e.g., He, H 2 ,O 2 ,N 2 , and CO 2 ) with increasing filler content shows that the trend is related to the true silica volume and void volume fraction. Crown

“…The films were initially dried at ambient temperature for two days, then removed from the glass dish and placed in a vacuum oven at 70 • C to remove any residual solvent. Thereafter, the films were immersed in methanol for 2 h at ambient conditions to reverse prior film formation history, in a manner similar to protocols previously developed for microporous polyacetylenes and PIM-1 [38][39][40]. After removal from methanol, the films were dried gradually at 70 • C in air, and weighed intermittently until constant weight was obtained.…”

Section: Polymer Film Preparationmentioning

confidence: 99%

Pure- and mixed-gas permeation properties of a microporous spirobisindane-based ladder polymer (PIM-1)

Thomas

Pinnau

et al. 2009

258

122

a b s t r a c t PIM-1, a glassy, spirobisindane-based ladder polymer is a novel intrinsically microporous membrane material. The pure-and mixed-gas permeation properties of PIM-1 are compared to those of highly permeable, microporous, linear chain, acetylene-based polymers, such as poly(1-trimethylsilyl-1-propyne) (PTMSP). PIM-1 exhibits very high permanent gas permeabilities coupled with moderate selectivities. For example, the oxygen permeability of PIM-1 at 25 • C is 1300 × 10 −10 cm 3 (STP) cm/cm 2 s cmHg combined with an oxygen/nitrogen selectivity of 3.8. Those values place PIM-1 above the Robeson trade-off curve for oxygen/nitrogen separation. Like microporous linear chain PTMSP, ladder-type PIM-1 is more permeable to large, condensable organic vapors, such as n-butane, than to small, permanent gases, such as methane. PIM-1 exhibits a mixed-gas n-butane/methane selectivity of up to 25, which is similar to that of PTMSP, the most permeable and selective polymer known for this separation. Because PIM-1 has significantly better solvent resistance than PTMSP, it could find applications as an advanced membrane material for the separation of organic vapor/permanent gas mixtures.