Functionalized Boron Nitride Nanosheets: A Thermally Rearranged Polymer Nanocomposite Membrane for Hydrogen Separation

Amino functionalized boron nitride nanosheets (FBN) were incorporated into a crosslinked, thermally rearranged polyimide (XTR) to fabricate FBN-XTR nanocomposite membrane. The FBN-XTR membrane exhibited a small decrease in H2 permeability but demonstrated a remarkably increased H2 gas selectivity over other gases, compared with XTR. The XTR membrane heat-treated at 425 °C had a H2 permeability of 210 Barrers and a H2/CH4 separation factor of 24.1, whereas the nanocomposite membrane with 1 wt % FBN exhibited a H2 permeability of 110 Barrers and H2/CH4 separation factor of 275, an order of magnitude greater. At 1 wt % FBN loading, the FBN-XTR membrane showed three times higher tensile strength and 60 % higher elongation than pristine XTR membrane. In addition, FBN-XTR was found to be able to be readily processed into thin-film membranes for practical H2 separation applications.