Crosslinking of Addition Copolymers From Tricyclononenes Bearing Si-Groups as a Modification of Membrane Gas Separation Materials

Here, we report the synthesis and the study of gas-transport properties of crosslinked highly permeable copolymers from Si-containing norbornene derivatives. The initial high-molecular-weight copolymers were prepared via addition copolymerization of 3-trimethylsilyltricyclot4.2.[1.0.sup.2,5]]non-7-ene (TCNSil) with 3-triethoxysilyttricyclo[4.2.[1.0.sup.2,5]]non-7-ene (TCNSiOEt) in good or high yields using a Pd-catalyst. The obtained copolymers included up to 10 mol% of TCNSiOEt units bearing reactive Si-O-C-containing substituents. The crosslinking was readily realized by using simple sol-gel chemistry in the presence of Sn-catalyst. The formed crosslinked copolymers were insoluble in common organic solvents. Permeability coefficients of various gases (He, [H.sub.2], [O.sub.2], [N.sub.2], C[O.sub.2], C[H.sub.4], [C.sub.2][H.sub.6], [C.sub.3][H.sub.8], n-[C.sub.4][H.sub.10]) in these copolymers before and after crosslinking were determined and the influence of the incorporated TCNSiOEt units as well as the crosslinking on gas transport properties were established. As a result, it was found that only a small reduction of gas-permeability was observed when TNCSiOEt units were incorporated into the main chains, and the copolymers were crosslinked. At the same time, the selectivity for [C.sub.4][H.sub.10]/C[H.sub.4] pair was increased. The suggested approach has allowed obtaining crosslinked polymers from Si-containing monomers without a loss of the main membrane characteristics.