Comparative studies of grafting and direct syntheses of inorganic-organic hybrid mesoporous materials

Journal Article · Mon Nov 01 04:00:00 EST 1999 · Chemistry of Materials

DOI:https://doi.org/10.1021/cm990369r· OSTI ID:20004033

Lim, M H; Stein, A

Vinyl-functionalized MCM-41 samples were prepared by either a postsynthesis grafting (PSG) process or a direct co-condensation synthesis. The structures, stabilities, and reactivities of products from both methods were compared. The mesoscopic order of the hexagonal pore structure of vinyl-grafted MCM-41 (v-gr-MCM-41) resembled that of the MCM-41 host. On the basis of powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), and bromination kinetics data, the vinyl groups appeared to be nonuniformly distributed in v-gr-MCM-41 prepared by the present PSG process, with a large proportion of vinyl groups on the external surface of the crystallites or inside channels but near the channel openings. The mesoscopic order of products from the direct synthesis (v-MCM-41) depended on the type of alkoxysilane precursor used and on the ratio of vinylsiloxane to alkoxysilane in the reaction mixture. The vinyl groups appeared to be more uniformly distributed in v-MCM-41. Vinyl-grafted MCM-41 exhibited greater hydrothermal stability than unmodified MCM-41 and was capable of adsorbing nonpolar solvents from aqueous mixtures or emulsions.

• Research Organization: Univ. of Minnesota, Minneapolis, MN (US)
• Sponsoring Organization: David and Lucille Packard Foundation; National Science Foundation; Department of Energy
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 20004033
• Journal Information: Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 11 Vol. 11; ISSN CMATEX; ISSN 0897-4756
• Country of Publication: United States
• Language: English

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