Polymer blends comprising polypropylene, Nylon 6, and a compatibilizer were extruded and biaxially stretched. The as-extruded films with various compositions were characterized in terms of morphology, crystallization behavior, optical transparency, and oxygen barrier property. The blend films with all five compositions presented matrix-dispersed morphology with polypropylene as the continuous phase when the Nylon 6 composition is less than 55 w.t. %. The morphology was reversed when Nylon 6 composition increased to 65 w.t. %. As-extruded films exhibited high optical transparency and good oxygen barrier properties. The blend films were then biaxially, sequentially drawn at 155 degrees C to draw ratio of 2.5 by 2.5. Stretching of one of the blend films containing 30% polypropylene, 55% Nylon 6, and 15% compatibilizer produced a microporous membrane with through-pore structure. The pore size of such membrane was around 100 nm with a porosity of 52%. Formation of through-pore structure was sensitive to both the composition and the process where blends with less Nylon 6 concentration or lower draw ratio would not yield through-pore structure. The generation of through pores were attributed to cavitation of polypropylene on the polypropylene-Nylon 6 interface. (C) 2017 Elsevier Ltd. All rights reserved.