Structure and gas transport characteristics of triethylene oxide-grafted polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene |
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| Authors: | Ding Tian Taliehsadat Alebrahim Gregory K. Kline Liwen Chen Haiqing Lin Chulsung Bae |
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| Affiliation: | 1. Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, USA;2. Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York, USA;3. Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA |
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| Abstract: | Polymeric membrane-based gas separation technology has significant advantages compared with traditional amine-based CO2 separation method. In this work, SEBS block copolymer is used as a polymer matrix to incorporate triethylene oxide (TEO) functionality. The short ethylene oxide segment is chosen to avoid crystallization, which is confirmed by differential scanning calorimetry and wide-angle X-ray scattering characterizations. The gas permeability results reveal that CO2/N2 selectivity increased with increasing content of TEO functional group. The highest CO2 permeability (281 Barrer) and CO2/N2 selectivity (31) were obtained for the membrane with the highest TEO incorporation (57 mol%). Increasing the TEO content in these copolymers results in an increase in CO2 solubility and a decrease in C2H6 solubility. For example, as the grafted TEO content increased from 0 to 57 mol%, the CO2 solubility and CO2/C2H6 solubility selectivity increased from 0.72 to 1.3 cm3(STP)/cm3 atm and 0.47 to 1.3 at 35°C, respectively. The polar ether linkage in TEO-grafted SEBS copolymers exhibits favorable interaction with CO2 and unfavorable interaction with nonpolar C2H6, thus enhancing CO2/C2H6 solubility selectivity. |
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| Keywords: | carbon dioxide ethylene oxide gas separation SEBS thiol-ene reaction |
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