Preparation of poly(ether‐block‐amide)/poly(amide‐<i>co</i>‐poly(propylene glycol)) random copolymer blend membranes for CO₂/N₂ separation

Abstract

A series of poly(amide‐ co ‐poly(propylene glycol)) (PA‐PPG) random copolymers with different content of PPG were designed by polycondensation reaction. These random copolymers were blended up to 60% with commercially available Pebax 2533. The blend membranes were characterized by Fourier‐transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), scanning electron microscope (SEM). Gas permeation properties of these blend membranes were investigated using five single‐gases (CO 2 , H 2 , O 2 , CH 4 , and N 2 ) at different temperature of 25–55°C and 1.0 atm. The impacts of content of PA‐PPG with different PPG content and operating temperature on CO 2 separation properties of Pebax/PA‐PPG blend membranes were studied. The results showed that CO 2 permeability gradually increased with the increasing operating temperature, whereas CO 2 permeability gradually decreased with the increase in content of PA‐PPG. CO 2 /N 2 selectivity gradually increased with the increase in content of PA‐PPG. In particular, Pebax/PA‐PPG (50)–60% displayed excellent CO 2 and O 2 separation properties ( P CO2 = 79.7 Barrer and P O2 = 13.6 Barrer, CO 2 /N 2 = 34.7 and O 2 /N 2 = 5.9) at 25°C and 1.0 atm. POLYM. ENG. SCI., 59:E14–E23, 2019. © 2018 Society of Plastics Engineers