Fabrication and Characterization of Polymer Blend Membranes for CO2/CH4 Separation

In the last two decades, various modifying techniques have been employed to improve membranes performance including mixed matrix, cross linking, grafting, polymer blending, making composite or hybrid membrane. Blending of polymeric membrane is a cost and time effective approach and an advanced technique for gas separation, where two or more polymers are mixed to produce a new material with different and desired physical, chemical and mechanical properties. This work reports on the separation performance of a novel polymeric blend membrane based on poly(amide-b-ethylene oxide) and polyethersulfone blends. These flat sheet membranes were synthesized using solution-casting in different ratios (10-40%) in order to improve membrane separation performance of CO2/CH4 gas mixtures. Prepared membranes were then characterized by Fourier Transformed Infra-Red Spectroscopy (FTIR) where spectral changes indicated existence of molecular interaction among the polymeric blends, highlighting their compatible nature. Permeabilities of pure gases (CO2 and CH4) were also examined at room temperature. Results indicated that increasing wt.% PES in the Pebax®/PES blend membranes increased selectivity of CO2/CH4 and decreased pure gas permeabilities.