UV-Raman and 29Si NMR Spectroscopy Investigation of the Nature of Silicate Oligomers Formed by Acid Catalyzed Hydrolysis and Polycondensation of Tetramethylorthosilicate
| Autor: | Anouschka Depla, Johan A. Martens, Michel Waroquier, Kristof Houthoofd, Marc Van Houteghem, Veronique Van Speybroeck, Christine E. A. Kirschhock, Elke Verheyen, An Veyfeyken |
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| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Condensation polymer
Chemical shift 02 engineering and technology Nuclear magnetic resonance spectroscopy 010402 general chemistry 021001 nanoscience & nanotechnology Condensation reaction 01 natural sciences 6. Clean water Silicate 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials chemistry.chemical_compound Hydrolysis General Energy chemistry Polymerization Polymer chemistry Molecule Organic chemistry Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | The Journal of Physical Chemistry C |
| ISSN: | 1932-7447 |
| DOI: | 10.1021/jp200568j |
| Popis: | Tetramethylorthosilicate (TMOS) was hydrolyzed and polymerized under strongly acidic conditions in the presence of substoichiometric quantities of water. The polymerization reaction was monitored during 64 h using 29Si NMR and UV-Raman spectroscopy. The nature of the oligomers and the condensation reaction pathways were unraveled using this combination of experimental techniques together with molecular modeling. 29Si NMR and UV-Raman signals which previously were not documented in literature could be assigned. TMOS rapidly was converted into short straight methoxylated silicate chains. Subsequently the growth of oligomers proceeded by condensations between a hydrolyzed middle group of a chain with an end-group of another chain. Larger oligomers were attached to each other via condensations between middle groups generating multiply branched structures. Rings were formed late in the reaction scheme through internal condensations of sizable silicate molecules. Oligomers that were characteristic of the differ... |
| Databáze: | OpenAIRE |
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