Etude des phases silicatées du ciment hydraté sous haute pression et haute température

ST ETIENNE-ENS des Mines (422182304) / SudocPARIS-BIUSJ-Thèses (751052125) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Hydration of tricalcium silicate (C 3 S) at high temperature and high pressure

International audienceHydration products of tricalcium silicate (C 3 S) are the calcium silicate hydrates (C-S-H) and Portlandite. Silica fume, added to anhydrous cement in industrial formulations reacts with Portlandite and leads to C-S-H different from the previous one. C 3 S hydration with and without silica fume has been studied under high pressure (1000 bar) and high temperature (160 • C) by numerous techniques (29 Si and 1 H NMR, XRD, Thermal analysis, SEM) for different hydration times. In these conditions, high temperature more stable crystalline phases are formed and their kinetics of formation is dependent on pressure. Besides, electrical conductivity measurement on hydrating cement under pressure have been carried out in order to evidence the great dependence of hydration kinetics with pressure. This study proposes a practical phase diagram which allows on a thermodynamical base to understand the change of equilibrium temperature with pressure. The kinetics of reaction has been studied and mechanisms of reaction proposed to explain the results. C 2002 Kluwer Academic Publisher

Interface tuning and stabilization of monoglyceride mesophase dispersions: Food emulsifiers and mixtures efficiency

Several food surfactants were examined as possible efficient emulsifiers for liquid crystalline monolinolein-based particles and as alternative choices to the non-food-grade emulsifier conventionally used Pluronic (R) F127. We described a food emulsifiers' toolbox, investigating their ability to emulsify mesophases (stabilization capacity, particle size, zeta potential) and their impact on internal nanostructures (from swelling to drastic modifications). Among the selected surfactants, sucrose stearate (S1670) was found to be the best candidate for replacing in a long term F127 as an efficient stabilizer of lipid particles. The emulsification performed by mixing F127 with S1670 or sodium caseinate (NaCas), and S1670/NaCas helped to discriminate their respective role in the particles and so their efficiency for the stabilization. In case of S1670 as co-emulsifier no strong structural modification was observed, while using F127 (25 wt% NaCas) an unexpected hexagonal mesophase was highlighted in self-assemblies. The evolution of zeta potentials by varying the mesophase and the emulsifier also informed about the distribution of co-surfactants in the particles. We thus reported submicronic nanostructured systems (from 100 to 350 nm) that were fully food-grade and possibly contained limonene, with a surface charge from -70 to -5 mV. (C) 2017 Elsevier Inc. All rights reserved

Nanostructured monolinolein miniemulsions as delivery systems: Role of the internal mesophase on cytotoxicity and cell internalization

International audienc