Nanocomposite membranes were prepared by incorporation of commercial poly(ethylene glycol) functionalized polyoctahedral oligomeric silsesquioxanes (PEG-POSS) in two grades of poly(ether-block-amide) namely PEBAX ® MH 1657 and PEBAX ® 2533. Single gas permeabilities of N 2 , O 2 , CH 4 , H 2 , and CO 2 were measured using the time-lag method. CO 2 permeability increased two fold after incorporation of 30 wt% PEG-POSS in PEBAX ® MH 1657, while the selectivity was not significantly affected at 30 °C. Simultaneous enhancement in permeability and selectivity was observed up to 30 wt% loading of PEG-POSS in PEBAX ® 2533 at 30 °C. The effect of temperature upon CO 2 permeability and CO 2 selectivity over N 2 , O 2 , CH 4 and H 2 was studied between 30 ºC to 70 °C. Substantial influence upon the thermal transition of the polyether domain of both polymers was observed due to incorporation of PEG-POSS by differential scanning calorimetry (DSC). Atomic force microscopy was used to evaluate the impact of 30 wt% PEG-POSS loading upon the surface topography of both investigated grades of PEBAX ®. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to study the membrane morphology and the distribution of the nanofillers (PEG-POSS) in PEBAX ® membranes.

The present work reports on the gas transport behavior of mixed matrix membranes (MMM) which were prepared from multi-walled carbon nanotubes (MWCNTs) and dispersed within polymers of intrinsic microporosity (PIM-1) matrix. The MWCNTs were chemically functionalized with poly(ethylene glycol) (PEG) for a better dispersion in the polymer matrix. MMM-incorporating functionalized MWCNTs (f-MWCNTs) were fabricated by dip-coating method using microporous polyacrylonitrile membrane as a support and were characterized for gas separation performance. Gas permeation measurements show that MMM incorporated with pristine or functionalized MWCNTs exhibited improved gas separation performance compared to pure PIM-1. The f-MWCNTs MMM show better performance in terms of permeance and selectivity in comparison to pristine MWCNTs. The gas permeances of the derived MMM are increased to approximately 50% without sacrificing the selectivity at 2 wt.% of f-MWCNTs' loading. The PEG groups on the MWCNTs have strong interaction with CO2 which increases the solubility of polar gas and limit the solubility of nonpolar gas, which is advantageous for CO2/N2 selectivity. The addition of f-MWCNTs inside the polymer matrix also improved the long-term gas transport stability of MMM in comparison with PIM-1. The high permeance, selectivity, and long term stability of the fabricated MMM suggest that the reported approach can be utilized in practical gas separation technology.

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:

Membrane‐based separation of organic molecules with 1–2 nm lateral dimensions is a demanding but rather underdeveloped technology. The major challenge is to fabricate membranes having distinct nanochannels with desired functionality. Here, a bottom‐up strategy to produce such a membrane using a tailor‐made triblock terpolymer featuring miscible end blocks with two different functional groups is demonstrated. A scalable multifunctional integral asymmetric isoporous membrane is fabricated by the solvent evaporation‐induced self‐assembly of the block copolymer combined with nonsolvent‐induced phase separation. The membrane nanopores are readily functionalized using positively and negatively charged moieties by two straightforward gas–solid reactions. The pores of the post‐functionalized membranes act as target‐specific functional soft nanochannels due to swelling of the polyelectrolyte blocks in a hydrated state. The membranes show unprecedented separation selectivity of small molecules based on size and/or charge which demonstrates the potential of the proposed strategy to prepare next‐generation nanofiltration membranes.

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Three grades of PolyActive block copolymers are investigated for CO2 separation from light gases. The polymers are composed of 23 wt % poly(butylene terephthalate) (PBT) and 77 wt % poly(ethylene glycol terephthalate) (PEGT) having the poly(ethylene glycol) segments of 1500, 3000, and 4000 g/mol, respectively. A commercial PEG POSS (poly(ethylene glycol) functionalized polyoctahedral oligomeric silsesquioxanes) is used as a nanofiller for these polymers to prepare nanocomposites via a solvent casting method. Single gas permeabilities of N2, H2, CH4, and CO2 are measured via the time-lag method in the temperature range from 30 to 70 °C. The thermal transitions of the prepared membranes are studied by differential scanning calorimetry (DSC). It is found that the length of PEG segment has a pronounced influence on the thermal transition of the polymers that regulates the gas separation performance of the membranes. The stability of the nanocomposites is also correlated with the thermal transition of the polyether blocks of the polymer matrices.

a b s t r a c tTailor-made block copolymer nanocomposite membranes are prepared by incorporation of 40 wt% methoxy poly(ethylene glycol) (PEG) functionalized polyoctahedral oligomeric silsesquioxanes (POSS) nanoparticles in commercial thermoplastic elastomer multiblock copolymer PEBAX s MH 1657. Atomic force microscopy was used to find out the location of the nanoparticles in the block copolymer matrix. Separation of CO 2 from N 2 and H 2 is studied by measurements of single gas transport properties of nanocomposite materials using the time-lag method in the temperature range 30-70 1C. PEG functionalized POSS nanoparticles increase the CO 2 permeability of the nanocomposite membranes without loss of CO 2 /N 2 and CO 2 /H 2 selectivity. Thermal properties of the nanocomposite membranes are studied by differential scanning calorimetry (DSC) to assess the stability of the nanocomposite membranes upon melting of polyether and polyamide blocks.

of biobased diols with phosgene derivatives [2,4] and the catalytic copolymerization of sustainable epoxides and CO 2 . [5,6] The copolymerization of biobased epoxides and CO 2 is of particular interest as it combines the use of biobased raw materials and the reduction of CO 2 . The anthropogenic emission of CO 2 accumulates to 32 Gt each year, which is caused mainly by the incineration of carbon matter. CO 2 is a greenhouse gas that contributes significantly to the warming of the earth's atmosphere. [7] Global warming increases chances of catastrophic weather phenomena and a rising sea level and, thus, impacts on our everyday life dramatically. Measures have been taken to reduce the emission and to contain the rise of CO 2 levels in the atmosphere in the last few decades. Part of these measures can be described by the concepts of carbon capture and storage/utilization (CCS/CCU). [8][9][10] The CCU deals with the separation and transformation of CO 2 from process gases (e.g., combustion gases in power plants and natural gas) to prevent emission of the greenhouse gas into the atmosphere. The separation step is achieved by the use of either chemical/physical absorbents or organic/inorganic membrane materials. [9,11] The class of absorbents is dominated nowadays by alkanol amine solutions, for example, monoethanolamine and diethanolamine, which require high temperatures for regeneration of the solvent. [12,13] Hence, these "wet-scrubbing" processes are connected to a considerable energy penalty that adds to the total emission of CO 2 . [14] The more energy-efficient-though less developed-technology relies on the use of membrane materials that separate CO 2 from other process gases by size exclusion (mostly hybrid metal-organic frameworks) [15,16] or solubility/diffusivity mechanisms (polymeric membranes), respectively. [17,18] The latter comprise a group of polymeric materials that exhibit permeabilities P (rate of transport through the matrix) and selectivities α (preference of one gas over the other; in this article the "ideal selectivity" is calculated as the ratio of two permeabilities) extending over several orders of magnitude. [19] However, those materials suffer frequently from low long-term stability, known as aging, which has prevented industrial application so far. [20] The large volumes of CO 2 captured in the industrial processes are either stored in gas-tight (often natural) basins (CCS) [10] or transformed into high-value chemicals via various chemical routes (CCU). Some of those routes are The biobased poly(limonene carbonate) (PLimC) synthesized by catalytic copolymerization of trans-limonene oxide and CO 2 unifies sustainability, carbon capture and utilization of CO 2 in one material. Films of PLimC show surprisingly high gas permeation and good selectivity. Additionally, it is not only very permeable to gases, but also to light, while simultaneously being a good heat insulator and mechanically strong, representing a novel type of material that is defined here as "breathing glass." Hence, this stud...