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Interactions organo-aluminates dans les ciments. Intercalation de polyméthacrylate-g-PEO dans l'hydrocalumite.

Abstract : Superplasticizers are used for cement hydration in order to increase the workability. Part of the SP is immobilized in one of the first hydrated phase: the OH-AFm phase, coming from the hydration of C3A. The OH-AFm phase is a lamellar double hydroxide presenting positively charged layers. The interlayer space then contains anionic species. The SP we are working with are polymethacrylates graft PEO polymers which are negatively charged and can thus interact with the AFm phase. In this work we focus on the interactions between the OH-AFm phases and these SP, varying the grafting ratio and the graft chains length of the polymers. We established the intercalation of SP in the AFm phase by XRD and NMR. The SP conformation between the layers can be described from the adaptation of the blobs model, which describes the polymers in solution. This model in solution was validated by the measurement of radius of gyration of polymers from SANS curves. We followed the speed of polymer sorption, performed isotherms of SP adsorption and studied the stability of the composite in presence of sulfates anions. Whatever their graft chains length and their grafting ratio, the time necessary for the polymers to be adsorbed is the same. At the maximum of the isotherms, the compensation of the positive charge of the mineral layer increases with the charge density of the polymer. And finally, if the SP-AFm phase is more stable than the OH-AFm phase, it appears that, in presence of sulphates, the polymer is released after several hours in solution and the monosulfoaluminate is formed. C3A hydration in presence of polymer leads to the formation of a compound having a similar structure than the SP-AFm phases synthesized by coprecipitation. We can thus expect the same kind of SP-AFm interaction in both compounds.
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Contributor : Claire Giraudeau <>
Submitted on : Friday, December 4, 2009 - 11:07:41 AM
Last modification on : Saturday, September 26, 2020 - 11:44:05 PM
Long-term archiving on: : Thursday, June 17, 2010 - 7:18:50 PM

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  • HAL Id : tel-00438620, version 1

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Claire Giraudeau. Interactions organo-aluminates dans les ciments. Intercalation de polyméthacrylate-g-PEO dans l'hydrocalumite.. Matériaux. Université Pierre et Marie Curie - Paris VI, 2009. Français. ⟨tel-00438620⟩

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