10.1021/acsomega.8b00632.s001 Hiroki Inde Hiroki Inde Masakoto Kanezashi Masakoto Kanezashi Hiroki Nagasawa Hiroki Nagasawa Toshimi Nakaya Toshimi Nakaya Toshinori Tsuru Toshinori Tsuru 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 American Chemical Society 2018 Gas Permeation Properties Thermally Stable Amorphous SiOC Structure N 2 atmosphere oxidative stability network pore size CF Amorphous SiOC networks SF gas permeation properties N 2 adsorption SiOC membrane calcined 2018-06-13 13:57:58 Journal contribution https://acs.figshare.com/articles/journal_contribution/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/6509681 A 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–CHCH<sub>2</sub> groups, and a crosslinking reaction of Si–CH<sub>3</sub> groups, respectively. The crosslinking of Si–CH<sub>3</sub> groups at temperatures ranging from 600 to 700 °C under a N<sub>2</sub> atmosphere was quite effective in constructing a Si–CH<sub>2</sub>–Si unit without the formation of mesopores, which was confirmed by the results of N<sub>2</sub> adsorption and by the gas permeation properties. The network pore size of the SiOC membrane calcined at 700 °C under N<sub>2</sub> showed high oxidative stability at 500 °C and was appropriate for the separation of large molecules (H<sub>2</sub>/CF<sub>4</sub> selectivity: 640, H<sub>2</sub>/SF<sub>6</sub>: 2900, N<sub>2</sub>/CF<sub>4</sub>: 98). A SiOC membrane calcined at 800 °C showed H<sub>2</sub>/N<sub>2</sub> 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.