Separation of CO2 from natural gas within the field of membrane technology has been carried out for a long time. For efficient separation of CO2/CH4, high-performance gas separating membranes are desired. The blending technique enhances the chemical and thermal stability, also taking heed in the improvement of separation properties with the economic sustainability. This research studies the perm-selective performance of polymeric blend membranes, glassy polymer (polysulfone) and rubbery polymer (polyvinyl acetate) with monoethanolamine (MEA). The polymeric amine blend membranes with enhanced properties were synthesized with different blending ratios in dimethylacetamide (DMAc) solvent. In this study, various compositions of polyvinyl acetate (PVAc) ranging from 5 to 20 wt. were blended with polysulfone (PSU) and MEA, and were used for the formation of flat sheet membranes via evaporation method. The gas permeation results showed that the CO2 permeance increased with increasing feed pressure. © 2018 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria