Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-25T17:50:32.287Z Has data issue: false hasContentIssue false
  • English
  • Français

Catalytic Control of SiO2 Sol-Gel Kinetics - a Mechanistic Study of Bases

Published online by Cambridge University Press:  28 February 2011

Jorge Sanchez ,
Mary Reese  and
Alon Mccormick
Jorge Sanchez
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
Mary Reese
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
Alon Mccormick
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
Get access

Abstract

The aim of this research was to determine the relative effects of three different base catalysts (NaOH, NH4OH, and RbOH) on the rate of gelation of SiO2 from reactive silicon ethoxide solutions in alcohol (the sol/gel method). The time to gelation was determined using a reaction protocol which assured that condensation was the rate controlling step. NMR spectroscopy was used to verify that the nature of the reacting polymers remained similar as the base catalyst was varied. It was determined that under these conditions the condensation reactions avoid diffusional limitations. Furthermore, the base catalyst serves to modulate both the activation energy and also the Arrhenius preexponential factor. This leads to the proposal of a new condensation mechanism.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 180: Symposium A – Better Ceramics Through Chemistry IV , 1990 , 263
Copyright
Copyright © Materials Research Society 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1 a. Brinker, C. J., Keefer, K. D., Schaefer, D. W. and Ashley, C.S., J. Non-Cryst. Sol., 63, 45, 1984.Google Scholar
1 b. Brinker, C. J., Keefer, K. D., Schaefer, D. W. and Ashley, C.S., J. Non-Cryst. Sol., 48, 47, 1982.Google Scholar
1 c. Brinker, C. J., Ward, K. J., Keefer, K. D., Holupka, E. and Bray, P. J., ACS Polym. Prep., 28 (1), 428, 1986.Google Scholar
2. Iler, R. K., “The Chemistry of Silica,” Wiley, New York, 1980.Google Scholar
3. Keefer, K. D., in “Better Ceramics Through Chemistry”, MRS Symp. Proc Vol. 32, Elsevier, 1984, p. 15.Google Scholar
4. Klein, L. C., Ann. Rev. Mat. Sci., 15, 227, 1985.Google Scholar
5. Sowman, H. G., Ceramic Bulletin, 67 (12), 1911, 1988.Google Scholar
6. Uhlmann, D. R. and Rajendran, G.P., in “Ultrastructure Processing of Advanced Ceramics” (Mackenzie, J. D. and Ulrich, D. R., eds.), Wiley, New York, 1987, p. 241.Google Scholar
7. Assink, R. A. and Kay, B. D., J. Non-Cryst. Sol., 99, 359, 1988.Google Scholar
8. Balfe, C.A. and Martinez, S.L., in “Better Ceramics Through Chemistry II”, MRS Symp. Proc. Vol. 73, Mat. Res. Soc, 1986, p. 27.Google Scholar
9. Basil, J. D. and Lin, C. -C., in “Ultrastructure Processing of Advanced Ceramics” (Mackenzie, J. D. and Ulrich, D. R., eds.), Wiley, New York, 1987, p. 783.Google Scholar
10. Kelts, L. W., Effinger, N. J. and Melpoder, S. M., J. Non-Cryst. Sol., 83, 353, 1986.Google Scholar
11. Klemperer, W. G., Mainz, V. V. and Millar, D. M., in “Better Ceramics Through Chemistry II”, MRS Symp. Proc. Vol. 73, Mat. Res. Soc, 1986, p. 15.Google Scholar
12 a. Pouxviel, J. C. and Boilot, J. P., J. Non-Cryst. Sol., 94, 374, 1987.Google Scholar
12 b. Pouxviel, J. C. and Boilot, J. P., J. Non-Cryst. Sol., 89, 345, 1987.Google Scholar
12 c. Pouxviel, J. C. and Boilot, J.P., in “Ultrastructure Processing of Advanced Ceramics” (Mackenzie, J. D. and Ulrich, D. R., eds.), Wiley, New York, 1987,, p.197.Google Scholar
13. Turner, C. W. and Franklin, K. J., J. Non-Cryst. Sol., 91, 402, 1987.Google Scholar
14. McGrath, J. E., in “Ultrastructure Processing of Advanced Ceramics” (Mackenzie, J. D. and Ulrich, D.R., eds.), Wiley, New York, 1987, p.55.Google Scholar
15. Atkins, P.W., “Physical Chemistry”, Oxford Press, Oxford, 1978.Google Scholar
16. Miller, D. R. and Macosko, C.W., Macromolecules, 9, 206, 1976.Google Scholar
17. McCormick, A. V. and Bell, A. T., Catalysis Reviews, 31 (1), 97 (1989).Google Scholar
18. Colby, M. W. and Mackenzie, J. D., J. Non-Cryst. Sol., 82, 37, 1988.Google Scholar
19. Barrer, R. M., “Hydrothermal Chemistry of Zeolites,” Butterworths, London, 1982.Google Scholar