New high Performance Gas Separation membrane Prepared From Novel Reaction Route

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For creation of gas separation membrane with a high performance, we started to prepare novel membrane materials from our original reaction routes. Relation between the polymer structure and their characteristics was also investigated in detail.Using-4-methylstirene as starting material, several types of Si-containing stirene monomers were synthesized. From gas permeability measurements of the polymer membrane thus obtained, polystirene with bis (trimethylsilyl) methyl group at para position (polySi2) showed fairly high gas permeability (P_<O2>=45 barrer) . Affinity of oxygen molecule toward organosilicon moiety is one of the reason to show such high gas permeability. Actually, with increasing Si-content in the polystirene membrane, the solubility of oxygen increased. However, the polystirene with three Si atoms in each monomeric unit (PolySi3) showed one order of magnitude low permeability than polySi2. It is very curious that PolySi3 showed low Tg (90ﾟC) than that of polySi2 (160ﾟC). Contrary to the large free space of polySi2, polySi3 may decrease free space due to the packing by the flexible side chains.Copolymerization of Si-containing stirenes with methacryloyl chloride provided reactive copolymers with acid chloride moiety as pendant groups with desired extent.Interfacial polycondensation of the copolymer thus obtained with diamines gave ultra thin films. Such ultra thin film is promising as gas separation membrane wit high flux.