Blending PPO‐based molecules with Pebax MH 1657 in membranes for gas separation

ABSTRACT This work explores the possibilities to blend block copolymers, i.e., Pebax MH 1657, with a variety of cheap poly(propylene oxide)‐rich molecules which could potentially play a double role in the resulting membranes as dispersing/stabilizing agents in multi‐component casting solutions and as a gas transport medium in the final membrane. These membranes were prepared by solution casting and were characterized by differential scanning calorimetry, scanning electron microscopy, atomic force microscopy, X‐ray diffraction, density measurements, and Fourier transform infrared‐attenuated total reflection, while additive incorporation was also studied with theoretical calculations. Gas permeation measurements showed that this approach resulted in increased permeabilities at the expense of mixed‐gas selectivity. An interpretation of the blend structure was finally made using gas transport models. The compatibility of these additives with the synthesis of selective gas separation membranes may enable a potential double role in membrane synthesis, i.e., as stabilizing agents in membrane synthesis and as a gas transport medium in the final membrane. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46433.