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Characterization of Microporous Silica Gels Prepared from Modified Silicon Alkoxides

Published online by Cambridge University Press:  25 February 2011

W. G. Fahrenholtz  and
D. M. Smith
W. G. Fahrenholtz
Affiliation:
UNM/NSF Center for Micro-Engineered, Ceramics University of New Mexico, Albuquerque, NM 87131
D. M. Smith
Affiliation:
UNM/NSF Center for Micro-Engineered, Ceramics University of New Mexico, Albuquerque, NM 87131
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Abstract

Organically modified silica gels were prepared from mixtures of TEOS and methyl-substituted silicon alkoxides. The pore structure of dried gels was investigated in order to determine the effect of the organic additions on gel structure. For base catalyzed gels, surface area, pore volume, and skeletal density all showed dramatic decreases at high methyl contents. The surface area dropped by nearly three orders of magnitude, from over 800 m2/g for normal silica gels to less than 1 m2/g for gels containing over 60 mole percent modified alkoxide. The pore structure of acid catalyzed gels showed less dependence on composition. The nature of the surface of both acid and base catalyzed gels varied with modified alkoxide content. Higher organic contents produced materials that were more hydrophobic. In addition, the mechanical strength of acid catalyzed gels dropped in direct proportion to methyl content.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 271: Symposium N – Better Ceramics Through Chemistry V , 1992 , 705
Copyright
Copyright © Materials Research Society 1992

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References

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