(695f) CO2 Selective Membranes Composed of Crosslinked or Supported CO2-Philic Oligomers

Membranes could be an integral part of the pre-combustion and post-combustion capture of CO2 during the process of coal gasification/water-gas-shift reaction which transforms coal, oxygen and water feed streams into hydrogen for fuel and CO2 for sequestration. The objective of this work is to design polymeric membranes that have very high CO2 permeability and high selectivity toward CO2 (i.e. very low H2 and N2 permeability). It is our hypothesis that the favorable thermodynamic interactions that enable certain polymers to dissolve in dense CO2 at extremely high pressure will also allow membranes composed of these polymers to exhibit high CO2 permeability at low pressure. Candidates include supported liquid membranes composed of poly(ethylene glycol) (PEG), poly(propylene glycol)(PPG), poly(butylenes glycol)(PBG), perfluoro polyether (PFPE), poly(dimethyl siloxane), poly(acetoxy oxetane) (PAO) and glycerol triacetate (GTA) and the rubbery membranes composed of the crosslinked analogs of the liquid polymers (with the exception of PAO and GTA) analogs. Solid films of poly (perfluoroacrylate) (PFA) were also tested. These polymers constitute the most CO2-philic polymers that have been identified to date. were determined for the PFA membrane, the supported liquid membranes of all of the liquid polymers,. Results of mixed gas permeability and selectivity values for CO2/H2 and CO2/N2 gas pairs will be discussed.

For the supported liquid membranes, PEGDME has shown the best performance in terms of CO2 permeability and selectivity over H2; whereas PDMS exhibited the highest permeability with a lower CO2/H2.

For the crosslinked membranes, the linear PBGdiacrylate (PBGDA) had the best performance with a CO2 permeability. The highest permeability was achieved with crosslinked PDMS.