High-Performance Thin Film Composite Membranes With Well-Defined Poly(dimethylsiloxane)-b-Poly(ethylene glycol) Copolymer Additives for CO2 Separation

A series of well-defined diblock copolymers (BCPs) consisting of poly(ethylene glycol) (PEG) and poly(dimethylsiloxane) (PDMS) were synthesized and blended with commercially available PEBAX (R) 2533 to form the active layer of thin-film composite (TFC) membranes, via spin-coating. BCPs with a PEG component ranging from 1 to 10 kDa and a PDMS component ranging from 1 to 10 kDa were synthesized by a facile condensation reaction of hydroxyl terminated PEG and carboxylic acid functionalized PDMS. The BCP/PEBAX (R) 2533 blends up to 50 wt % on cross-linked PDMS gutter layers were tested at 35 degrees C and 350 kPa. TFC membranes containing BCPs of 1 kDa PEG and 1-5 kDa PDMS produced optimal results with CO2 permeances of approximately 1000 GPU which is an increase up to 250% of the permeance of pure PEBAX (R) 2533 composite membranes, while maintaining a CO2/N-2 selectivity of 21. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1500-1511