Skip to Main content Skip to Navigation
Theses

Synthèse et étude de matériaux nanostructurés à base d'acétate de cellulose pour applications énergétiques

Abstract : Nanostructured materials have unique properties (high exchange areas, containment effect...) because of their very low characteristic dimensions. The elaboration way set up in this PhD work consists in applying the classical processes for the preparation of aerogel-like materials (combining sol-gel synthesis and CO2 supercritical extraction) to cellulosic polymers. This work is divided in four parts: a literature review, the presentation and the study of the chemical synthesis that leads to cellulose acetate-based aerogel, the characterizations (chemical, structural and thermal) of the elaborated nanomaterials, and finally the study of the first carbons that were obtained after pyrolysis of the organic matrix. The formulations and the sol-gel protocol lead to chemical gels by crosslinking cellulose acetate using a polyfunctionnal isocyanate. The dry materials obtained after solvent extraction with supercritical CO2 are nanostructured and mainly mesoporous. Correlations between chemical synthesis parameters (reagent concentrations, crosslinking rate and degree of polymerisation) and porous properties (density, porosity, pore size distribution) were highlighted thanks to structural characterizations. An ultraporous reference aerogel, with a density equals to 0,245 g .cm-3 together with a mesoporous volume of 3,40 cm3 .g-1 was elaborated. Once in granular shape, this material has a thermal conductivity of 0,029 W .m-1 .K-1. In addition, carbon materials produced after pyrolysis of the organic matrix and after grinding are nanostructured and nanoporous, even if important structural modifications have occurred during the carbonisation process. The elaborated materials are evaluated for applications in relation with energy such as thermal insulation (organic aerogels) but also for energy conversion and storage through electrochemical way (carbon aerogels).
Document type :
Theses
Complete list of metadatas

Cited literature [159 references]  Display  Hide  Download

https://pastel.archives-ouvertes.fr/pastel-00002212
Contributor : Ecole Mines Paristech <>
Submitted on : Thursday, May 10, 2007 - 8:00:00 AM
Last modification on : Thursday, September 24, 2020 - 5:22:02 PM
Long-term archiving on: : Thursday, September 30, 2010 - 8:05:45 PM

Identifiers

  • HAL Id : pastel-00002212, version 1

Citation

Florent Fischer. Synthèse et étude de matériaux nanostructurés à base d'acétate de cellulose pour applications énergétiques. Sciences de l'ingénieur [physics]. École Nationale Supérieure des Mines de Paris, 2006. Français. ⟨NNT : 2006ENMP1420⟩. ⟨pastel-00002212⟩

Share

Metrics

Record views

1721

Files downloads

12763