(681d) Carbon Capture Performance of Crosslinked Polyphosphazene Blend Membranes

Thiol-ene photopolymerization was a highly effective technique to cross-link gummy polyphosphazene elastomers containing methoxyethoxyethoxy (MEE) side groups. The solid material has a pure gas CO₂ permeability of 610 barrer and CO₂/N₂ selectivity of 35 at 40°C. The immediate benefit of this facile cross-linking technique was enabling the material to be applied as a solid selective coating on a porous membrane support. In this talk, we will demonstrate recent exciting advances we have achieved with this membrane. The material was successfully tested under coal-derived flue gas at the National Carbon Capture Center, demonstrating stable performance over 500 hours of continuous testing. The material performance has been characterized with mixed gases containing various levels of humidity: gas permeability decreased with increasing humidity, and was fully reversible, with selectivity remained barely changed. Finally, we successfully fabricated a thin film composite membrane with CO₂ permeance of 1200 gpu with CO₂/N₂ selectivity of 31. The membrane performance, monitored over 2000 hours, did not exhibit reduction due to physical aging because of the rubbery nature of the coating material.