Synthesis and Characterization of PES/Pebax-MWCNTs Mixed Matrix Membranes for Gas Separation

The development of MWCNT mixed matrix membranes (MWCNT-MMMs) has shown good performance for gas separation. Interfacial interactions between the CNTs and the polymer and the dispersion of the MWCNTs in the polymeric matrix affects the overall performance of CNT mixed matrix membranes. Although CNTs properties are superior to other inorganic fillers but due to their chemically inert properties and inability to disperse in typical organic solvents, their applicability in industry is still uncertain. Typically, nanotubes are bound together by strong van der Waals interactions and form tight bundles. Therefore, MWCNTs tend to accumulate to each other in polymer matrix. This has been the biggest challenge in development of MWCNT-MMMs in producing defect free membranes. In this research, PES/Pebax-MWCNTs mixed matrix membraness were fabricated to capture carbon for natural gas. Sorbitol has been utilized in the fabrication of membranes to break the agglomeration of MWCNTs. In this study, the effect of MWCNTs loading and addition of sorbitol on the structure of synthesized membranes was analyzed using FESEM, DSC and FTIR. The incorporation of MWCNTs in the polymer matrix allows more active path for small molecules to flow across the membranes. The agglomeration of MWCNTs is more significant with the increase of fillers loading. Addition of sorbitol improved the morphology of membranes. Smooth surface of membranes with no agglomeration are observed for all MWCNTs loading (2-6 wt%). Glass transition temperature (Tg) was shifted to lower temperature with the addition of both MWCNTs and sorbitol.