The Interaction of Alkoxy Silane Coupling Agents with Silica Surfaces
MONSANTO RESEARCH CORP ST LOUIS MO
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The interactions of gamma-aminopropyltriethoxy silane A-1100, gamma-methacryloxtrimethoxy silane A-174, gamma-glycidoxytrimethoxy silane A- 187, and ethyltriethoxy silane A-15 with silica surfaces have been studied by means of infrared spectroscopy. The results indicate that the major force holding the silane to the silica surface after application from dilute solutions is primany chemical bonding. These bonds are formed by a condensation reaction between silanols on the hydrolyzed form of the silane and hydroxyl groups on the silica surface. In the case of the amino-silane A-1100, hydrogen bonding was found to exist but was of minor importance in bonding the silane to the surface. In studying the effects of the addition of water, acetic acid, or n-propylamine to the treating solution, it was found that n-propylamine has a unique catalytic effect on this reaction. This catalytic effect explains the observation that gamma-aminopropyltriethoxy silane is more reactive than the other silanes studies. It is felt that silanes not containing an amine group can be made more effective if they are applied in the presence of an amine catalyst.
- Organic Chemistry
- Laminates and Composite Materials