Steric hindrance effect on amine demonstrated in solid polymer membranes for CO2 transport

Due to steric hindrance effect, aqueous solutions of sterically hindered amines have demonstrated superior advantages for carbon dioxide absorption over unhindered amines and hence have been used in commercial gas treating processes to remove CO2 from syngas and natural gas. This work for the first time reports the effect of amine steric hindrance demonstrated in a solid phase. The steric hindrance effect dramatically enhanced the CO2 transport of hindered polyamines in the solid polymeric matrix of new fixed-site-carrier facilitated transport membranes synthesized by blending hindered polyamines with crosslinked polyvinylalcohol. The new membranes exhibited significantly improved CO2/H2 and CO2/N2 separation performances at 110 °C and a feed pressure of 2 atm. This work could provide significant opportunities for further fundamental work to fully exploit sterically hindered amines and open a new approach for the development of next generation gas separation membranes.