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Polyethylene glycols have received worldwide attention as a highly permeable CO2-philic polymer in carbon dioxide separation applications. In this study, we investigated the influence of a low molecular weight polyethylene glycol (PEG 200) on physicochemical, morphological, and gas separation properties of Matrimid®5218 as a novel polymer blend. Both symmetric and asymmetric Matrimid flat sheet membranes with 0-20 wt.% PEG were prepared via a dense film-casting method. The miscibility of blends at low PEG concentrations (3-5 wt.%) was confirmed by differential scanning calorimetry (DSC) and polarized light microscopy (PLM). Moreover, the blends were partially miscible at higher PEG concentrations (10-20 wt.%). Matrimid/PEG molecular interactions were further studied by FTIR and XRD analysis. SEM images indicated an impressive influence of PEG on the symmetric structure of Matrimid membrane. An asymmetric structure with a dense thin skin layer and a highly porous sub-layer was observed for the blends containing 10-20 wt.% PEG. The CO2 permeability and CO2/CH4 selectivity of the best-yield CO2-selective blend membrane (Matrimid/PEG (95:5)) incvreased about 25% (from 7.68 to 9.62 Barrer) and 15% (from 35 to 40) compared to pure Matrimid, respectively. Furthermore studying the plasticization pressures of the membranes revealed that the more PEG content in blend the less the plasticization pressure obtained. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

The effect of LMW polyethylene glycol (PEG 200) as a CO 2 -philic polymer on the gas separation properties of Matrimid ® 5218/ZSM-5 MMM was investigated. Hybrid ternary membranes were fabricated considering various compositions of PEG 200 and ZSM-5 zeolite via dense film casting method. The effect of the calcination of ZSM-5 was determined by FTIR analysis. Possible interactions in Matrimid/PEG 200/ZSM-5 system and phase changes in Matrimid microstructure were further studied by FTIR and XRD, respectively. According to FESEM images increment in PEG content (15 wt.%) resulted in nanoparticles agglomeration and formation of pores in the dense structure of Matrimid, while at lower content of PEG (<5 wt.%), a uniform dispersion of nanoparticles and a good compatibility between ZSM-5/polymers was observed. The results revealed that the CO 2 permeability and CO 2 /CH 4 selectivity of pure Matrimid was significantly enhanced with low-level loadings of calcined ZSM-5 and small portions of PEG in to the membrane structure. The CO 2 permeability and CO 2 /CH 4 selectivity of the best-yield hybrid ternary membrane (Matrimid/PEG (95:5) + 5 wt.% ZSM-5) increased about 50% (from 7.68 to 11.53 Barrer) and 72% (from 34.9 to 60.1) compared to pure Matrimid, respectively. [ABSTRACT FROM AUTHOR]

The drive toward greater application of membrane has resulted in its rapid development in natural gas processing industry. In this work, amine-mediated membranes were tailored for CO2 removal from CO2/CH4 stream. The effects of various parameters such as amine concentration, microporous support, feed pressure and composition were examined to study the permeation behavior of pure and mixed gases. Generally, CO2 transport through the DEA-PVA membranes was higher than that of MEA-PVA membranes for approximately 70%. The membrane containing 15 wt% DEA and 35 wt% MEA revealed higher permselectivity. CO2 permeance enhancement of amine-PVA membranes in comparison with neat PVA membrane, confirmed that CO2-amine reaction was the dominant transport mechanism. Additionally, with increasing feed pressure, CO2/CH4 permselectivity decreased due to carrier saturation. However, lower partial pressure of CO2 was in favor of reaction mechanism in pure and mixed gas tests. On the other hand, CH4 is not significantly affected by feed pressure confirming that solution-diffusion is the governing transport mechanism. Additionally, PTFE support with higher wettability showed better performance (+8%) regardless of amine type, concentration and feed pressure. DEA-PVA membrane has exhibited good stability during 2 weeks, unlike MEA-impregnated membrane, which was probably due to carrier degradation over time. POLYM. ENG. SCI., 54:1268-1279, 2014. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Abstract: CO2 removal from different gas streams via the polymeric membranes has been propounded as an important issue in greenhouse gas emissions control, natural gas upgrading, and enhanced oil recovery. Here, polymeric blend membranes were prepared from acrylonitrile–butadiene–styrene (ABS) and poly vinyl acetate (PVAc), and their CO2/N2 and CO2/CH4 separation characteristics were investigated. The influence of different PVAc contents on gas separation performance and the effect of pressure, ranging from 1 to 8bar, on CO2 permeability were studied. Furthermore, the morphology of the membranes was analyzed by FTIR, XRD, DSC and SEM. It was shown that the highest CO2 permeability of 5.72 Barrer for the membrane containing 10wt.% PVAc, the highest CO2/CH4 selectivity was 29 in 20wt.% PVAc and CO2/N2 was 40.41 in 30wt.% PVAc contents. These results comprised from different effective factors such as PVAc acetate polar groups, compactness in polymer matrix at the presence of high molecular weight PVAc, and the acrylonitrile and flexible butadiene contents of ABS. Furthermore, in the transmembrane pressure of 2–8bar the CO2 permeability approximately descended with the pressure increase for PVAc content of 0–40wt.%, and it ascended for 50–60wt.%. Generally, the prepared membranes can be taken into account as better membranes for CO2/N2 separation than CO2/CH4. [Copyright &y& Elsevier]

Carbon dioxide capture and storage (CCS) has been propounded as an important issue in greenhouse gas emissions control. In this connection, in the present article, the advantages of using polymeric membrane for separation of carbon dioxide from CO2/N2 streams have been discussed. A novel composition for fabrication of a blend membrane prepared from acrylonitrile-butadiene-styrene (ABS) terpolymer and polyethylene glycol (PEG) has been suggested. The influence of PEG molecular weight (in the range of 400 to 20000) on membrane characteristics and gas separation performance, the effect of PEG content (0-30 wt%) on gas transport properties, and the effect of feed side pressure (ranging from 1 to 8 bar) on CO2 permeability have been studied. The results show that CO2 permeability increases from 5.22 Barrer for neat ABS to 9.76 Barrer for ABS/PEG20000 (10 wt%) while the corresponding CO2/N2 selectivity increases from 25.97 to 44.36. Furthermore, it is concluded that this novel membrane composition has the potential to be considered as a commercial membrane. [ABSTRACT FROM AUTHOR]