NOVEL HIGHLY PERMSELECTIVE 6F-POLY(AMIDE-IMIDE)S AS MEMBRANE HOST FORNANO-SIZED CATALYSTS

Poly(amide-imide)s (PAIs) combine properties of amide and imide polyme rs. On a synthetic route starting with preformed imide monomers (as di carboxylic acids) and diamines, PAIs are readily available in various structures and different properties. Hexafluoroisopropylidene (6F) uni ts are element of the dicarboxylic acid or diamine part or both parts of the PAI. Tailoring of the polymer was achieved to high permselectiv ities and ability to generate nano-sized noble metal catalysts in high amounts, > 20 wt% noble metal, inside the polymer membranes. Even at high catalyst loading, the films remained flexible. Gas permeabilities up to 15 barrer for O-2 (p(O2)/p(N2) = 5.4) and 100 barrer for H-2 (p (H2)/p(N2) = 35) and selectivities up to 7.6 for p(O2)/p(N2) (p(O2) = 1.8 barrer) and 100 for p(H2)/p(N2) (p(H2) = 23 barrer) were measured. Gas permeability and selectivity data of CH4, N-2, O-2, He, H-2 and C O2 are reported. In addition, various salts in amounts up to 50 wt% we re incorporated into the films and chemically transformed to catalysts . These catalysts generated inside the membrane were homogeneously dis tributed, still active and homogeneous in size (similar to 2 nm). The influence of salts and catalysts on the gas permeation properties of t hese nonporous membranes is discussed and their catalytic activity is shown by hydrogen sorption. Thin film composite membranes on PVDF supp orts with and without catalyst were prepared and their permselectivity data are reported.