ao8b00632_si_001.pdf (104.36 kB)
Tailoring a Thermally Stable Amorphous SiOC Structure for the Separation of Large Molecules: The Effect of Calcination Temperature on SiOC Structures and Gas Permeation Properties
journal contribution
posted on 2018-06-13, 13:57 authored by Hiroki Inde, Masakoto Kanezashi, Hiroki Nagasawa, Toshimi Nakaya, Toshinori TsuruA SiOC
membrane with high oxidative stability for gas separation
was tailored by utilizing vinyltrimethoxysilane, triethoxysilane,
and 1,1,3,3-tetramethyldisiloxane as Si precursors. Amorphous SiOC
networks were formed via the condensation of Si–OH groups,
the hydrosilylation of Si–H and Si–CHCH2 groups, and a crosslinking reaction of Si–CH3 groups, respectively. The crosslinking of Si–CH3 groups at temperatures ranging from 600 to 700 °C under a N2 atmosphere was quite effective in constructing a Si–CH2–Si unit without the formation of mesopores, which
was confirmed by the results of N2 adsorption and by the
gas permeation properties. The network pore size of the SiOC membrane
calcined at 700 °C under N2 showed high oxidative
stability at 500 °C and was appropriate for the separation of
large molecules (H2/CF4 selectivity: 640, H2/SF6: 2900, N2/CF4: 98).
A SiOC membrane calcined at 800 °C showed H2/N2 selectivity of 62, which was approximately 10 times higher
than that calcined at 700 °C because the SiOC networks were densified
by the cleavage and redistribution reactions of Si–C and Si–O
groups.