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Séminaire SIMM- Tatiana Budtova (Mines, CEMEF)
4 avrilJeudi 4 avril de 14h00 à 15h00 - HolweckSéminaire SIMM
Tatiana Budtova
PSL Research University, MINES Paris, Center for Materials Forming (CEMEF), UMR CNRS 7635, CS 10207, 06904 Sophia Antipolis, France"Polysaccharide aerogels : an overview"
Aerogels are fascinating materials that are usually described with the adverb “very” : very low density (around 0.1 g/cm3 and lower), very high porosity (above 90%) and very high surface area of pores (several hundred m2/g). Classical aerogels are inorganic (the most popular being based on silica) or based on synthetic polymers. At the beginning of the 21st century new aerogels were made : they are bio-based, and for the time being the majority are based on polysaccharides.
The first studies on bio-aerogels were devoted to cellulose : aerogels were made via cellulose dissolution in various solvents. Since that time other polysaccharides (starch, pectin, alginate, hyaluronic acid, chitosan) were used to make aerogels, and various applications were tested : for thermal insulation, as carbons for electro-chemical applications, as drug carriers, etc. An overview of the current status and prospects in bio-aerogels will be made. -
SOUTENANCE DE THESE DE MAXIME BES
11 marsVendredi 5 avril de 12h00 à 18h00 - Holweck -
Séminaire SIMM
28 févrierJeudi 11 avril de 14h00 à 15h00 - Charpak -
Séminaire SIMM - Nathan Ferrandin Schoffel (SIMM)
13 févrierJeudi 7 mars de 14h00 à 15h30 - CharpakNathan Ferrandin Schoffel (SIMM)
Aminosilanes as a one-pot treatment for simultaneous deacidification and strengthening of heritage papersAcidity is a major issue in the preservation of paper-based collections. A large number of paper documents of mediocre quality produced in the late 19th and early 20th century are very acidic and brittle, their public access hence being drastically restricted. To find a solution for these documents, treatments based on copolymerized aminoalkylalkoxysilanes (AAASs), which allow simultaneous deacidification and mechanical strengthening of paper, have been developed at Centre de Recherche sur la Conservation (CRC) and Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI). As these treatments showed efficacy for some papers but not for others, the results had to be better understood before a possible use by the conservation professionals.
My PhD project (2017-2021) advanced the understanding of the interactions/reactions between AAASs and the cellulosic substrate, with a better identification of the parameters that reduce the treatment efficacy. To that purpose, AAAS treatments were applied to newsprint lignocellulosic papers of complex compositions, and NMR and FTIR were used to characterize the physicochemical bonds formed in-situ. In conjunction, the evolution of the physicochemical properties (pH, optical and mechanical properties) of a large range of papers treated several years ago were studied. Finally, several options for optimized formulations of the AAAS treatments were tested, including the use of reducing and deacidifying agents as pre-treatments for paper and thermal post-treatment sequences. -
DEMI JOURNEE SCIENTIFIQUE SIMM
29 novembre 2023Lundi 18 décembre 2023 de 08h00 à 13h00 - Holweck