Articles & Issues
- Language
- English
- Conflict of Interest
- In relation to this article, we declare that there is no conflict of interest.
- Publication history
-
Received July 31, 2001
Accepted September 20, 2001
-
This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0) which permits
unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright © KIChE. All rights reserved.
All issues
Fabrication and Thermophysical Characterization of Nano-Porous Silica-Polyurethane Hybrid Aerogel by Sol-Gel Processing and Supercritical Solvent Drying Technique
Department of Chemical Engineering, Sogang University, C.P.O. Box 1142, Seoul 121-742, Korea
Korean Journal of Chemical Engineering, January 2002, 19(1), 159-166(8), 10.1007/BF02706890
Download PDF
Abstract
Thermally and mechanically enhanced nanoporous silica-polyurethane hybrid aerogel was synthesized by sol-gel processing and low temperature supercritical CO2 drying. A partially condensed silica solution and a polymeric MDI were used as the raw materials with a tertiary amine as a catalyst and 1,4-dioxiane as a dilution solvent. After the gelation reaction was completed, aged wet hybrid aerogel was dried by a low temperature supercritical CO2 drying technique. Also, thermophysical characteristics such as density, BET surface area, and thermal conductivity as a function of catalyst ratio and aging time of the synthesized hybrid aerogel were analyzed. It was found that, at a fixed target density, the lowest average pore size of the aerogel, 8 nm, was obtained when the catalyst ratio was 0.1 wt.%. Also, at these conditions, the BET surface area showed the highest surface area, 287.3 m2/g. It was found that with decreasing average pore size and with increasing BET surface area, thermal conductivity tends to decrease. At pressure 1 torr, the sample aerogel showed the lowest thermal conductivity, 0.0184 W/mK.
Keywords
References
Biesmans G, Randall D, Francais E, Perrut M, J. Non-Cryst. Solids, 225, 36 (1998)
Brinker CJ, Drotning DW, Scherer GW, "A Comparison Between the Densification Kinetics of Colloidal and Polymeric Silica Gels," Better Ceramics Through Chemistry I, Brinker, C.J., Clark, D.E. and Ulrich, D.R., eds., North-Holland, New York (1984)
Brinker CJ, Scherer GW, "Sol-Gel Science," Academic Press Inc., Boston (1990)
Carslaw HS, Jaeger JC, "Conduction of Heat in Solids," 2nd ed., Chap. 10, Oxford University Press, London (1959)
Grazzini G, Balocco C, Lucia U, Int. J. Heat Mass Transf., 39(10), 2009 (1996)
Hrubesh LW, J. Non-Cryst. Solids, 225, 335 (1998)
Iler RK, "Chemistry of Silica," John Wiley & Sons, New York (1978)
Kim SY, Yeo DH, Lim JW, Yoo KP, Lee KH, Kim HY, J. Chem. Eng. Jpn., 34(2), 216 (2001)
Kistler SS, Nature, 127, 741 (1931)
Lee KH, Kim SY, Yoo KP, J. Non-Cryst. Solids, 186, 18 (1995)
Schwertfeger F, Glaubitt W, Schubert U, J. Non-Cryst. Solids, 145, 85 (1992)
Tillotson TM, Hrubesh LW, J. Non-Cryst. Solids, 145, 44 (1992)
Tillotson TM, Hrubesh LW, Thomas IM, "Partially Hydrolyzed Alkoxysilanes as Precursors for Silica Aerogels," Better Ceramics Through Chemistry III, Brinker, C.J., Clark, D.E., and Ulrich, D.R., eds., MRS, Pittsburgh (1988)
Tewari PH, Arlon JH, "Process for Forming Transparent Aerogel Insulating Arrays," U.S. Patent, 4,610,863 (1986)
Tewari PH, Hunt AJ, Loffuts KD, "Advance in Production of Transparent Silica Aerogels for Window Glazing," Proceedings of the 1st International Symposium on Aerogels, Wurzburg (1985)
Woods G, "The ICI Polyurethanes Book," 2nd ed., ICI Polyurethanes (1990)
Yokogawa H, Yokoyama M, J. Non-Cryst. Solids, 186, 23 (1995)
Brinker CJ, Drotning DW, Scherer GW, "A Comparison Between the Densification Kinetics of Colloidal and Polymeric Silica Gels," Better Ceramics Through Chemistry I, Brinker, C.J., Clark, D.E. and Ulrich, D.R., eds., North-Holland, New York (1984)
Brinker CJ, Scherer GW, "Sol-Gel Science," Academic Press Inc., Boston (1990)
Carslaw HS, Jaeger JC, "Conduction of Heat in Solids," 2nd ed., Chap. 10, Oxford University Press, London (1959)
Grazzini G, Balocco C, Lucia U, Int. J. Heat Mass Transf., 39(10), 2009 (1996)
Hrubesh LW, J. Non-Cryst. Solids, 225, 335 (1998)
Iler RK, "Chemistry of Silica," John Wiley & Sons, New York (1978)
Kim SY, Yeo DH, Lim JW, Yoo KP, Lee KH, Kim HY, J. Chem. Eng. Jpn., 34(2), 216 (2001)
Kistler SS, Nature, 127, 741 (1931)
Lee KH, Kim SY, Yoo KP, J. Non-Cryst. Solids, 186, 18 (1995)
Schwertfeger F, Glaubitt W, Schubert U, J. Non-Cryst. Solids, 145, 85 (1992)
Tillotson TM, Hrubesh LW, J. Non-Cryst. Solids, 145, 44 (1992)
Tillotson TM, Hrubesh LW, Thomas IM, "Partially Hydrolyzed Alkoxysilanes as Precursors for Silica Aerogels," Better Ceramics Through Chemistry III, Brinker, C.J., Clark, D.E., and Ulrich, D.R., eds., MRS, Pittsburgh (1988)
Tewari PH, Arlon JH, "Process for Forming Transparent Aerogel Insulating Arrays," U.S. Patent, 4,610,863 (1986)
Tewari PH, Hunt AJ, Loffuts KD, "Advance in Production of Transparent Silica Aerogels for Window Glazing," Proceedings of the 1st International Symposium on Aerogels, Wurzburg (1985)
Woods G, "The ICI Polyurethanes Book," 2nd ed., ICI Polyurethanes (1990)
Yokogawa H, Yokoyama M, J. Non-Cryst. Solids, 186, 23 (1995)
