Solvent Selection and the Control of Sol-Gel Reactions

Abstract

The hydrolysis and gelation sequence occurring in the formation of a filament or a rigid coherent gel from an organic silicate requires a mutual solvent for the organicsilicate and water if it is to proceed successfully. The solvent is usually a water-miscible alcohol. This alcohol can also be a reaction product, which makes the sequence very solvent dependent. The best control of both hydrolysis and gelation is obtained when the alcohol solvent and the organic silicate each contain the same alkoxy group. The gel resulting is also the best binder for refractory grain. Suitable systems are ethyl silicate and ethanol also isopropyl silicate and isopropanol. The formation of rigid coherent gels, or filaments which on firing convert to ceramic fibres, from hydrolysates of ethyl silicate and aluminium chlorhydrate species is also very solvent dependent. With glycol solvents, aluminium chlorhydrates do not form filaments nor ceramic fibres. With ethanol as solvent, aluminium chlorhydrate-polyol complexes readily form rigid coherent gels and filaments, hence ceramic fibres, because the polyol complex is formed by displacing coordinated water in the aluminium chlorhydrate. This reduces the amount of water available for reaction, which optimises filament and fibre formation.

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References

  1. 1.

    H.G. Emblem and K. Jones, Trans. J. Brit. Ceram. Soc., 79 (4), Ivi (1980).

    Google Scholar 

  2. 2.

    H.G. Emblem, A.K. Das and K. Jones, U.S. Patent No. 4 211 717 (8 July 1980).

  3. 3.

    H.G. Emblem, Silicates Industriels, 44, 286 (1979).

    Google Scholar 

  4. 4.

    K. Jones, H.G. Emblem and H.M. Hafez, J. Non-Cryst. Solids, 63, 201 (1984).

    CAS  Article  Google Scholar 

  5. 5.

    H.G. Emblem, Ceramurgia International, 1, 136 (1975).

    CAS  Article  Google Scholar 

  6. 6.

    K.D. Biddle, A.K. Das, K. Jones and H.G. Emblem, J. Appl. Chem. Biotechnol., 27, 565 (1977).

    CAS  Article  Google Scholar 

  7. 7.

    Revlon Inc., British Patent No. 1 009 959 (17 November 1965).

  8. 8.

    J.M. Boulton, K. Jones and H.G. Emblem, J. Mater. Sci., 24, 979 (1989).

    CAS  Article  Google Scholar 

  9. 9.

    J.M. Boulton, Ph.D Thesis, University of Manchester, 1987.

  10. 10.

    J.M. Boulton, H.G. Emblem and K. Jones, British Patent No. 2 173 179A (8 October 1986).

  11. 11.

    H.G. Emblem, K. Jones and J.M. Boulton, U.S. Patent No. 4 810 441 (7 March 1989).

  12. 12.

    H.G. Emblem, K. Jones and J.M. Boulton, British Patent No. 2 210 034A (1 June 1989).

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Correspondence to K. Jones.

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Jones, K., Boulton, J.M. & Emblem, H.G. Solvent Selection and the Control of Sol-Gel Reactions. MRS Online Proceedings Library 180, 277 (1990). https://doi.org/10.1557/PROC-180-277

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