Pebax-PEG-MWCNT hybrid membranes with enhanced CO2 capture properties

Three-component hybrid membranes comprising Pebax, poly (ethylene glycol) (PEG)-based polymers and multi-walled carbon nanotube (MWCNT) were prepared by simple physical mixing of Pebax solution and MWCNT-containing PEG-based polymer solution. Scanning electron microscope (SEM) images showed an improved dispersion of MWCNT within polymer matrix arisen from the hydrophilic modification of PEG-based polymers. The embedded MWCNT disrupted the polymer chain packing and decreased polymer crystallinity, which was confirmed by X-ray diffraction, influences of PEG-based polymer type on CO2, N-2 and CH4 permeations were investigated: incorporating high molecular weight PEG-based polymers favored CO2/CH4 separation, while incorporating low molecular weight PEG-based polymers favored CO2/N-2 separation. All the hybrid membranes displayed enhanced CO2 permeability owing to the increased amorphous phase. With the incorporation of MWCNT, CO2/CH4 selectivity was decreased for the enhanced chain mobility, while CO2/N-2 selectivity was increased for the increased amorphous PEO content. In particular, for P-PEGDME(40)-CNT(5) membrane, a CO2/N-2 mixed gas selectivity of 108 and CO2 permeability up to 743 Barrer at 10 bar and room temperature were acquired, which showed promising prospect for CO2 capture. (C) 2014 Elsevier B.V. All rights reserved.