In silica-rubber based nanocomposites, a single organo-silicon is often used to compatibilize and covalently link silica to rubber. In this work, we have investigated the impact, at micro- and macroscales, of the decoupling of the hydrophobization and the coupling activity of silane by pretreating silica with two different silane chemistries. The first one, a mercaptosilane, is the coupling agent that promotes a covalent link between silica and rubber during the sulfur-mediated vulcanization reaction.
View Article and Find Full Text PDFCombinatorial approach has been widely recognized as a powerful strategy to develop new-higher performance materials and shed the light on the stoichiometry-dependent properties of known systems. Herein, we take advantage of the unique features of chemical beam vapor deposition to fabricate compositionally graded Na1+xTaO3±δ thin films with −0.6 < x < 0.
View Article and Find Full Text PDFThe improvement of mechanical properties of polymer-based nanocomposites is usually obtained through a strong polymer-silica interaction. Most often, precipitated silica nanoparticles are used as filler. In this work, we study the synergetic effect occurring between dual silica-based fillers in a styrene-butadiene rubber (SBR)/polybutadiene (PBD) rubber matrix.
View Article and Find Full Text PDFIn this paper, an original homemade system is presented in detail for the electrical and thermoelectrical characterizations of several types of materials from bulk to thin films. This setup was built using a modulated CO laser beam to probe the thermoelectric properties at different depths below the surface. It allows a simultaneous measurement of the electrical conductivity () and the Seebeck coefficient (), from room temperature up to 250 °C.
View Article and Find Full Text PDFThe electrochemical one-electron reduction of tert-nitrobutane in N,N'-dimethylformamide is a typical reaction, which has been shown to follow the quadratic model of outersphere electron transfer. The variation of the standard rate constant with temperature allows a separate determination of the reorganization energy and of the pre-exponential factor. The value found for the former is in agreement with independent estimates of the solvent and intramolecular reorganization energies.
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