Engineering Interfacial Interactions for Hydrogen Separation Enhancement in Torlon®/Mixed-Linker ZIF-8 Mixed Matrix Membranes

Polymer membranes traditionally used for gas separation can be easily fabricated via a solution process; however, they have limitations in gas separation performance. Mixed matrix membrane (MMM) with dispersed high-performance filler within a polymer matrix achieves both excellent separation efficiency and productivity. In this study, we employed Torlon® (polyamide-imide), a chemically stable and commercially available polymer, as the matrix of the membranes. To enhance the separation performance through the fabrication of MMM, we utilized 2abIm-mixed-linker ZIF-8 (ML-ZIF-8) as the filler particles to improve the interfacial interaction with the Torlon® matrix. FT-IR and XPS analyses on the Torlon®/ML-ZIF-8 MMM confirmed the occurrence of interactions between the Torlon® and ML-ZIF-8. As a result, the analysis of both the DSC and stress-strain curves confirmed the effectiveness of incorporating ML-ZIF-8 into the Torlon® for improving the stability of the polymer-filler interface. This enhancement resulted in an approximately 2.7 times higher H2 permeability for the Torlon®/ML-ZIF-8 MMM compared to the pure Torlon® membrane. Furthermore, the selectivity of H2/N2 and H2/CH4 separation increased by around 11 times and 9.6 times, respectively, leading to a significant overall improvement in separation performance.