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Enhanced gas permeability by fabricating mixed matrix membranes of functionalized multiwalled carbon nanotubes and polymers of intrinsic microporosity (PIM)
- Khan, Muntazim M., Filiz, Volkan, Bengtson, Gisela, Shishatskiy, Sergey, Rahman, Md.Mushfequr, Lillepaerg, Jelena, Abetz, Volker
- Journal of membrane science 2013 v.436 pp. 109-120
- artificial membranes, carbon dioxide, carbon nanotubes, diffusivity, mechanical properties, nitrogen, permeability, polyethylene glycol, scanning electron microscopy, solubility, sorption isotherms, thermogravimetry
- In this study, mixed matrix membranes (MMM) consisting of multi-walled carbon nanotubes (MWCNTs) embedded in PIM-1 matrix have been fabricated via solution casting method and their gas transport properties are investigated. The MWCNTs were chemically functionalized with polyethylene glycol (PEG) for a better dispersion in the polymer matrix. The effect of functionalized MWCNTs (f-MWCNTs) loading on gas permeation properties of the MMM were investigated by varying the MWCNTs loading in a PIM-1 matrix from 0.5 to 3.0wt%. 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 2wt% 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 CO₂ 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 CO₂/N₂ separation. The mechanical properties and experimental sorption isotherms of CO₂ and N₂ of the f-MWCNTs/PIM MMM were enhanced as well.