Development of novel fluorinated additives for high performance CO2 separation thin-film composite membranes

A series of poly(ethylene glycol)-block-poly(pentafluoropropyl acrylate) diblock copolymers were synthesized by Reversible Addition Fragmentation Chain Transfer (RAFT) polymerization. These block copolymers were blended up to 60 wt% with commercially available PEBAX 2533. The resulting polymer mixtures were successfully spin coated onto cross-linked polydimethylsiloxane (PDMS) gutter layers which in turn had been deposited onto a porous polyacrylonitrile (PAN) support, to form a thin film composite membrane. Gas testing of these membranes for carbon capture applications showed enhanced CO2 permeances up to 1830 GPU, without a significant drop in CO21N2 selectivity at 35 degrees C and 350 kPa, relative to a pure PEBAX upper layer. The impacts of temperature and pressure on membrane performance were investigated for temperatures from 25 degrees C to 55 degrees C and pressures from 100 kPa to 500 kPa. Theoretical calculations indicated that in the absence of a gutter layer, the upper layer could achieve a CO2 permeance of over 3000 GPU with a CO21N2 selectivity of 22. These results represent a significant increase in gas permeances compared with previously published results for similar membranes. (C) 2015 Elsevier B.V. All rights reserved.