Novel high performance mixed matrix nanocomposites membranes: its structural, morphology, thermal stabilities, mechanical properties, gas permeation and gas selectivity studies

Modified LDHs particles, including LDHamino benzoate (MLDHs) nanoparticles with the intercalated amino benzoate in the interlayer galleries are well exfoliated and show excellent compatibility in the polyimide (PI) matrix. Using FTIR spectroscopy, Xray diffraction (XRD), FESEM, and electron microscopy (TEM), we confirmed that MLDHs/PI nanocomposites were successfully synthesized. PI hybrid films with different contents of MLDHs nanoparticles (0, 3, 5 and 7 wt%) were compared in terms of their morphologies, thermal properties, and gas permeation and selectivity properties. We used TEM to evaluate the degree of intercalation and the amount of aggregation of the MLDHs nanoparticles. The MLDHs nanoparticles, for the most part, were well dispersed in the polymer matrix. Moreover, the addition of only a small amount of LDHs particles was enough to improve the thermal stabilities and mechanical properties of PI hybrid films. The thermooptical properties were measured by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and ultravioletvisible (UV–Vis) spectrometry. As anticipated, though the gas permeability of pure gases, such as He, N2, CH4 and CO2 exhibited a decrease, it was not monotonous. A marked decrease in permeability of gases such as CO2 and CH4, in comparison to relatively lower decrease in permeability of He, was observed, especially at higher LDH loading. An increase in selectivity: α(He/CO2) and α(He/CH4), especially at higher LDH loading indicated the capability of nanocomposites to tune the selectivity favorably.