Kinetic study of silica gels by a new rheological ultrasonic investigation
| Autor: | G. Gouedard, M. Gindre, J.-Y. Le Huérou, Stéphane Serfaty, Loic Martinez, Nicolas Wilkie-Chancellier, Emmanuel Caplain, Pascal Griesmar, P. Figuiere, C. Ould Ehssein |
|---|---|
| Přispěvatelé: | Université de Cergy Pontoise (UCP), Université Paris-Seine, Systèmes et Applications des Technologies de l'Information et de l'Energie (SATIE), École normale supérieure - Cachan (ENS Cachan)-Université Paris-Sud - Paris 11 (UP11)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-École normale supérieure - Rennes (ENS Rennes)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: |
Materials science
Acoustics and Ultrasonics Rheometer 02 engineering and technology Activation energy 010402 general chemistry 01 natural sciences Viscoelasticity Shear modulus Rheology Materials Testing Newtonian fluid Composite material ComputingMilieux_MISCELLANEOUS Ultrasonography [SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph] Silicon Dioxide 021001 nanoscience & nanotechnology 0104 chemical sciences [SPI.TRON]Engineering Sciences [physics]/Electronics Shear (sheet metal) Kinetics Ultrasonic sensor 0210 nano-technology Gels [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing Algorithms |
| Zdroj: | Ultrasonics Ultrasonics, Elsevier, 2006, 44, pp.e881-e885. ⟨10.1016/j.ultras.2006.05.035⟩ |
| ISSN: | 0041-624X |
| DOI: | 10.1016/j.ultras.2006.05.035⟩ |
| Popis: | The last decades have seen the development of sol–gel (SG) process currently used to develop new materials in a wide range of scientific applications. The SG process leads to an oxide macromolecular network through a sol (liquid phase) to gel transition. To optimize this process, the control of the kinetic of the chemical reaction is required. This kinetic can be deduced from the temporal evolution of the viscoelastic parameters. Upto date no complete investigation during the SG formation can be achieved by a unique non-destructive technique. In this paper, we present an ultrasonic technique to measure the viscoelastic parameters (storage G′ and loss G″ shear moduli) of the gel material during its formation. By using a suitable model which takes into account the mass loading on the surface, the viscoelastic parameters of these materials are accurately deduced. In order to study the efficiency of this technique, silica gels transition is monitored at various formation temperatures and for different initial hydrolysis molar ratio (h). In addition, the monitoring is performed at different oscillatory shear measurements in the 6–54 MHz frequency range to determine a new characteristic time tvs corresponding to the moment when the material is no more a newtonian liquid. This characteristic time is then compared to the gelation time tg determinated by rheological or acoustic audible range methods. Thus the new characteristic time is also a good criterion to characterize earlier the SG matrix transition. Our AT-cut quartz technique using our model can also be used as a high frequency rheometer for the sol–gel materials. |
| Databáze: | OpenAIRE |
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