Highly hydrophilic, rubbery membranes for CO2 capture and dehydration of flue gas

\u3cp\u3eThis paper reports the potential of highly hydrophilic, poly(ethylene oxide) based block copolymers for the simultaneous removal of CO\u3csub\u3e2\u3c/sub\u3e and water vapor from a ternary gas simulating a flue gas in a post-combustion capture configuration. Water vapor sorption measurements show strong sorption of water vapor in these block copolymers especially above a water vapor activity of 0.6. Mixed water vapor/gas permeability measurements as a function of water vapor activity were performed using binary (H\u3csub\u3e2\u3c/sub\u3eO/CO\u3csub\u3e2\u3c/sub\u3e and H\u3csub\u3e2\u3c/sub\u3eO/N\u3csub\u3e2\u3c/sub\u3e) and ternary (H\u3csub\u3e2\u3c/sub\u3eO/CO\u3csub\u3e2\u3c/sub\u3e/N\u3csub\u3e2\u3c/sub\u3e) feed mixtures. The water vapor permeability increased exponentially with the water vapor activity whereas the gas permeability in all cases slightly decreased. As the effect of the presence of water vapor was relatively stronger on the N\u3csub\u3e2\u3c/sub\u3e permeability, the CO\u3csub\u3e2\u3c/sub\u3e/N\u3csub\u3e2\u3c/sub\u3e selectivity increased slightly with increasing water vapor activity. No noticeable differences between the pure gas (from binary mixtures) and the mixed gas (from ternary mixtures) membrane performance have been observed. This indicates that plasticization effects, due to the sorption of CO\u3csub\u3e2\u3c/sub\u3e, are not significant at the low feed pressure (2.5bar) used. Also, increasing water content did not cause plasticization. Overall, the block copolymers studied in this work combine a high CO\u3csub\u3e2\u3c/sub\u3e permeability with a reasonable CO\u3csub\u3e2\u3c/sub\u3e/N\u3csub\u3e2\u3c/sub\u3e gas selectivity. Due to their highly hydrophilic character, they also have the ability to simultaneously remove CO\u3csub\u3e2\u3c/sub\u3e and water vapor from flue gases, which makes these PEO-ran-PPO based block copolymers an attractive membrane material for post-combustion CO\u3csub\u3e2\u3c/sub\u3e capture applications.\u3c/p\u3

Tuning of mass transport properties of multi-block copolymers for CO2 capture applications

Polyether and especially poly(ethylene oxide) (PEO) based segmented block copolymers are very well known for their high CO2 permeability combined with a high CO2/light gas selectivity, but most (commercially) available block copolymers have incomplete phase separation between the soft and hard blocks in the polymer leading to reduced performance. Here we present a polyether based segmented block copolymer system with improved phase separation behavior and gas separation performance using poly(ethylene oxide) (PEO) and/or poly(propylene oxide) (PPO) as a soft segment and short monodisperse di-amide (TΦT) as a hard segment.\ud \ud In this work we tune the mass transport properties of such multi-block copolymers for CO2 capture by systematically investigating the effect of the type and length of soft segment in the block copolymer at constant short hard segment. The effect of (1) the length of the PEO soft segment, (2) the type of soft segment (PPO vs. PEO) and (3) the use of a mixture of these two different types of soft segment as a method to tune the gas separation performance and its relation with the thermal–mechanical properties is investigated. The use of such a polyether based segmented block copolymer system as presented here offers a very versatile tool to tailor mass transfer and separation properties of membranes for gas and vapor separation

Polyelectrolyte/fluorinated polymer interpenetrating polymer networks as fuel cell membrane

International audienceOriginal membranes based on an interpenetrating polymer network (IPN) architecture combining a poly(2-acrylamido-2-methyl-1-propane sulfonic acid) (AMPS) network and a fluorinated network were synthesized. The AMPS weight compositions were varied from 50 to 70 wt%. The first network was achieved by radical copolymerization of AMPS with a fluorinated telechelic diacrylate while the second one was obtained by photoinitiated cationic copolymerization of telechelic fluorinated diepoxide with trimethylol propane triglycidyl ether. The morphologies of these different IPNs were deduced from small-angle X-ray scattering (SAXS) spectra and dynamic thermomechanical analysis (DMTA). The main functional properties related to their use as proton exchange membrane in fuel cells were quantified, such as water vapor sorption, liquid water uptake (22-59 wt%), proton conductivity (1-63 mS/cm), gas permeability (0.06 and 0.80 barrer for dry oxygen and hydrogen, respectively), and oxidative and thermal stabilities. More precisely, the effects of the ionic exchange capacity (IEC) varying from 1.73 to 2.43 meq/g and the cross-linking density of the conducting phase on the morphology and the properties of IPN membranes were studied in detail. Finally, these IPN membranes were tested as fuel cell membrane and a correlation between the ex-situ and in-situ characterizations was established