Multilayered gas separation membranes with alternating layers of beta crystalline polypropylene and PEBAX copolymers were produced via coextrusion and biaxial stretching for potential applications in modified atmosphere packaging. The number of layers and PEBAX compositions were varied to study the effect of various membrane configurations on pore formation in the polypropylene layers, which ideally serve as a mechanical support for the selective PEBAX layers. Gas permeabilities of multilayered films were compared to control PEBAX films using a simple model, which allowed inferences about the completeness of pore formation to be drawn. Preliminary results show that increasing the layer count degrades membrane throughput and separation capability, while varying PEBAX composition results in a tradeoff between these properties. (C) 2014 Elsevier Ltd. All rights reserved.