Copolyimide mixed matrix membranes with oriented microporous titanosilicate JDF-L1 sheet particles

JDF-L1 is a microporous titanosilicate exhibiting a layer structure with pore sizes of about 3 Å. It is consequently an attractive material to separate H2-containing mixtures. This is the reason why JDF-L1, after disaggregation by means of hexadecyltrimethylammonium surfactant, has been combined with a carboxyl group containing copolyimide (6FDA4MPD/6FDA-DABA 4:1) to produce mixed matrix membranes, which were applied to the separation of H2/CH4 and O2/N2 mixtures. Additionally, due to the sheet growth habit of JDFL1 crystals, a preferential horizontal orientation of the JDF-L1 filler particles dispersed into the polymer was expected. This preferential orientation, which was achieved when the polymer solution concentration used during the membrane casting process was relatively low, has been studied by optical and electronic microscopy, X-ray diffraction and polarized Raman spectroscopy.