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NANOCOMPOSITES POLY(DIMETHYLSILOXANE) - SILICE OU OXYDE DE TITANE GENERE IN SITU : SYNTHESE, STRUCTURE ET PROPRIETES

Abstract : This study examines and compares the behavior of two nanocomposites based on spherical particles (SiO2 and TiO2) generated in situ in a preformed PDMS matrix by the sol-gel process. The networks synthesis of PDMS-SiO2 and PDMS-TiO2 was carried out in the presence of several catalysts in order to get various morphologies. To control the reactions of synthesis, weighing and infrared spectroscopy were used. The morphology, the state of dispersion, the polymer-filler interaction as well as thermal degradation, mechanical properties were characterized and compared through several methods : 1) IR-transmission spectroscopy for the presence of water in the nanocomposites ; 2) MET and SAXS for the dispersion and morphology ; 3) DSC, RMN1H, TDSC and swelling measurements for the evaluation of the polymer-filler interface ; 4) ATG for thermal degradation ; 5) Uniaxial streteching and dynamics measurements for mechanical properties. Dierences and similarities were observed between PDMS-SiO2 and PDMS-TiO2 networks. Both types of networks lead to a good building with improved elastic moduli and fracture properties depending on the catalyst used. Differences appear in the tensile curves (with a plastic behavior more marked on the TiO2 samples) and no Payne effect is observed in PDMS-SiO2 networks unlike TiO2-PDMS networks. PDMS-SiO2 systems exhibit improved thermal properties compared to unfilled networks. Furthermore, this improvement is related to synthesis conditions including the nature of the catalyst. Indeed the improved thermal properties is greater in the samples catalyzed with the DEA. For PDMS-TiO2 samples, a degradation of thermal properties is observed : the samples filled with TiO2 degrade faster than the unfilled network and at lower temperatures. All the differences and similarities observed could be linked either to the nature of the filler, to their different morphology (particle size, existence of percolating network etc. ...) and to the quality of the interface PDMS-SiO2 or PDMS-TiO2.
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Contributor : Ecole Espci Paristech <>
Submitted on : Monday, March 21, 2011 - 11:20:08 AM
Last modification on : Wednesday, October 14, 2020 - 3:43:05 AM
Long-term archiving on: : Wednesday, June 22, 2011 - 9:54:58 AM

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  • HAL Id : pastel-00578502, version 1

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Amadou Lamine Diop. NANOCOMPOSITES POLY(DIMETHYLSILOXANE) - SILICE OU OXYDE DE TITANE GENERE IN SITU : SYNTHESE, STRUCTURE ET PROPRIETES. Chimie-Physique [physics.chem-ph]. Université Pierre et Marie Curie - Paris VI, 2010. Français. ⟨pastel-00578502⟩

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