The paper describes the performance of Pebax (R)/polyethylene glycol (PEG) blend thin film composite membranes for CO2 separation from gas mixtures containing H-2, N-2 and CH4. Membranes were tested at different conditions; temperature and pressure dependence of gas flux and selectivity were explored. The temperature dependence was correlated with the Arrhenius equation to determine the activation energy of single gas permeation. Single and mixed gas permeation was measured for different pressures at 293 K up to 20 bar. Improved permeabilities and CO2/H-2 selectivities were obtained in the newly developed composite membranes. (c) 2008 Elsevier B.V. All rights reserved.