Sol-gel polymerization in alkoxysilanes: 29Si NMR study and simulation of chemical kinetics

A. Vainrub, F. Devreux, J. P. Boilot, F. Chaput, M. Sarkar

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    25 Scopus citations

    Abstract

    We report on the results of 29Si NMR monitoring of alkoxysilane/ethanol/acid water sol-gels with tetraethoxysilane (TEOS), methyltriethoxysilane (MTEOS) and vinyltriethoxysilane (VTEOS). The gel time of the TEOS solution was 49 days at the degree of condensation c = 0.81, whereas MTEOS and VTEOS do not gel in spite of the high c = 0.95 achieved. The polymerization kinetics progressively slows with the time owing to the growth of sterical restrictions. To account for the effect we developed a kinetic model based on the reaction rates which explicitly decay as a function of the degree of condensation. The model describes the complete sol-gel process in all the studied systems including a gel transition in TEOS and aging of the gel.

    Original languageEnglish (US)
    Pages (from-to)197-200
    Number of pages4
    JournalMaterials Science and Engineering B
    Volume37
    Issue number1-3
    DOIs
    StatePublished - Feb 1996

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    Keywords

    • Alkoxysilanes
    • Models of chemical kinetics
    • Nuclear magnetic resonance
    • Sol-gels

    ASJC Scopus subject areas

    • Materials Science(all)
    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics

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