Correlation between polymer packing and gas transport properties for CO2/N2 separation in glassy fluorinated polyimide membrane

Gas separation performance of a membrane highly hinges on its physical properties. in this study,the interplay between polymer packing of a membrane and its gas transport behaviours (permeability and selectivity) was investigated through a series of 6fda-dam:daba (3:2) polyimide membranes with different polymer compactness. the chemical structure and the polymer packing of the resulting membrane were characterized using attenuated total reflectance-fourier transform infrared spectroscopy (atr-ftir) and packing density measurement,respectively. co2/n2 separation efficiency of the membrane was evaluated at 25°c with feed pressure up to 6 bar. n2 permeability was found to rely on the membrane’s packing density,which signified its greater dependence on molecular sieving. in contrast,sorption showed a more vital role in determining the co2 permeability. in this work,the membrane with a final thickness of 97±2 μm had successfully surpassed the robeson’s 2008 upper bound plot with a co2 permeability of 83 barrer and co2/n2 selectivity of 97 at 3 bar permeation. © school of engineering,taylor’s university.