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Preparation and high oxygen-enriching properties of cross-linking polydimethylsiloxane/SiO2 nanocomposite membranes for air purification


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Nanocomposite membrane based on polydimethylsiloxane (PDMS) and nanoscale SiO2 particles were prepared by a convenient and mild sol–gel copolymerization of tetraethoxysilane as well as cross-linking reaction. The oxygen-enriching properties of cross-linking PDMS/SiO2 nanocomposite membranes containing different silica conversion and SiO2 contents were investigated. The results showed that the nanocomposite membranes exhibited good membrane-forming ability, superior mechanical properties, and high solvent resistance as well as excellent oxygen-enriching properties for air purification. The oxygen-enriching performance was regulated by the organic/inorganic ratio and silica conversion in the sol–gel synthesis process. Permeability and selectivity could increase simultaneously with the addition of nanoscale SiO2. The oxygen permeation coefficient of the nanocomposite membrane increased to 680 Barrer and oxygen/nitrogen separation factor kept 3.0 or so, both higher than those of the corresponding pure PDMS membrane. The high oxygen-enriching properties of the nanocomposite membranes arose from the introduction of SiO2 particles, the sol–gel copolymerization, and cross-linking method. © 2012 American Institute of Chemical Engineers AIChE J, 59: 650–655, 2013