This study deeply investigates gas separation performance of neat and alloyed poly(Ether Block Amide) [PEBA] (grade 1657) membranes. Poly(ethylene glycol 600 diacrylate), [PEGDA], was used as alloying agent with different weight fractions, 20%, 40% and 60%, based on weight of the neat PEBA membrane. The main aim of this work is removing CO2 from syngas stream. Therefore, permeability, selectivity and activation energy of permeation for pure gases, CO2, H-2, CH4 and N-2, were studied within wide ranges of temperature, 25-75 degrees C, and pressure, 8-40 bar. The prepared PEBA and alloyed PEBA/PEGDA membranes were characterized by differential scanning calorimerry (DSC), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM), and X-ray diffraction (XRD) and dynamic mechanical thermal analysis (DMTA). Obtained results in this investigation showed that the alloyed membranes exhibit better separation performance compared with the neat PEBA membranes. (C) 2014 Elsevier B.V. All rights reserved.