Microporous membranes were produced from biaxial orientation of polymer blends comprising polypropylene (PP), polyamide 6 (Nylon 6), and polypropylene grafted maleic anhydride (PPgMA). During biaxial orientation, the continuous PP domains cavitated while the dispersed Nylon 6 domains remained rigid and spherical. The effect of blend composition on cavitation was analyzed and a ternary diagram generated to identify the composition range for through-pore formation. The effects of draw ratio and initial film thickness on membrane properties were also studied. The membranes were found to have adjustable porosity up to 62% with nanoscale size pores. The filtration performance was evaluated on such membranes with varied thickness. The membranes showed very high filtration efficiency on separating 50 nm Latex microbeads from water suspensions. (C) 2018 Elsevier Ltd. All rights reserved.