Effects of Pressure and Nanoparticle Functionality on CO 2 ‐Selective Nanocomposites Derived from Crosslinked Poly(ethylene glycol)

• Published in: Macromolecular chemistry and physics 2004-12, Vol.205 (18), p.2409-2419
• Main Authors: Patel, Nikunj P., Zielinski, John M., Samseth, Jon, Spontak, Richard J.
• Format: Article
• Language: English
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.200400356

Summary : Purification of H 2 generated from industrial gasification processes requires removal of CO 2 as the permeate from mixed CO 2 /H 2 streams to avoid costly H 2 repressurization. Such gas separation can be achieved through the use of reverse‐selective polymer membranes that exhibit high CO 2 affinity. In this work, the physical properties of CO 2 ‐selective membranes composed of poly(ethylene glycol) diacrylate (PEGda), as well as PEGda nanocomposites with 10 wt.‐% fumed silica (FS), are reported. Two PEGda oligomers differing in chain length and FS nanoparticles varying in surface functionality are exposed to CO 2 at low and high pressures to elucidate the roles of CO 2 pressure, network topology and nanoparticle aggregation on molecular transport and solubility. Results from swelling and sorption kinetics confirm that both penetrant diffusivity and solubility increase with increasing PEGda chain length and decreasing network density. Methacrylate‐terminated FS nanoparticles are more effective in improving rheological properties and retaining high CO 2 selectivity than hydroxyl‐terminated nanoparticles of comparable size. TGA profiles obtained from crosslinked PEGda membranes and their corresponding nanocomposites: PEGda575 (•), PEGda575 with 10 wt.‐% FSma (▴), PEGda700 (○), and PEGda700 with 10 wt.‐% FSma (▵). magnified image TGA profiles obtained from crosslinked PEGda membranes and their corresponding nanocomposites: PEGda575 (•), PEGda575 with 10 wt.‐% FSma (▴), PEGda700 (○), and PEGda700 with 10 wt.‐% FSma (▵).