Preparation and Gas Separation Properties of Melamine-Phthalaldehyde Porous Polymer/Polydimethylsiloxane Mixed Matrix Membrane

Melamine phthalaldehyde porous polymer (MA)/polydimethylsiloxane (PDMS) mixed matrix membranes (MMMs) were prepared using the solution casting method. The morphology of the membranes was examined using a scanning electron microscope (SEM). The gas separation performance of the prepared MA/PDMS MMMs with different MA contents was investigated. The results indicate that the incorporation of MA could improve the permeability/selectivity combinations of the PDMS membrane. On increasing the MA content, the permeability of the membranes increased, whereas, the separation selectivity increased at first and then decreased. The binary gas permeation test results showed that separation selectivities of 19.2 and 6.0 for CO2/N-2 and CO2/CH4, respectively, were achieved on the MA/PDMS (1.2% (w, mass fraction)) membrane. Additionally, the CO2 permeability reached up to 8100 Barrer, much higher than that of the pure PDMS membrane. The MA/PDMS (1.2% (w)) MMM surpasses the Roberson upper bound for CO2/N-2 separation.