Preparation of Organic/Inorganic Membrane by PDMS Low-temperature Pyrolysis

The organic/inorganic membranes were prepared via low-temperature pyrolysis of polymers. Firstly, polymeric membranes were prepared by dip-coating method using PDMS as the precursor and stainless steel as the support. Then they were pyrolyzed at 350–480℃ under inert atmosphere. The effects of preparation conditions on the gas separation performance of the organic/inorganic membranes were investigated. Chemical structure changes of PDMS in the pyrolysis process were studied by TG and FT-IR. The morphology of organic/inorganic membrane was characterized by SEM. The results showed that the organic/inorganic membranes with good gas separation performance could be successfully prepared by low-temperature pyrolysis of PDMS. The membrane retains part flexibility of PDMS, and presents good thermostability and high gas permselectivity. The gas separation performance and membrane layer structure of organic/inorganic membranes are greatly affected by the preparation conditions such as the PDMS concentration, coating times, pyrolysis temperature and properties of support. The gas separation performances prepared under the optimum condition are that the O2 permeation flux of 21.2 GPU(1 GPU=7.501 × 10-12 m3(STP)/(m2·s·Pa)) and O2 /N2 selectivity of 2.28.