MODIFICATION DE L'AMIDON PAR GREFFAGE DE DERIVES AROMATIQUES SOUS RAYONNEMENT IONISANT

The grafting of lignin onto starch using electron beam radiation was studied by analysing the reactivity of lignin models: cinamic alcohol, paramethoxybenzylic alcohol and p-benzenedimethanol on maltodextrins under electron beam activation. The products of the reaction were analysed by mass spectrometry MALDI-TOF & ESI as well as RMN spectrometry

VICENTE MAURICIO PADRÓN [Material gráfico]

ÁLBUM FAMILIAR CASA DE COLÓNCopia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201

Mineralogical and physico-chemical characterization of Mbodiene palygorskite for pharmaceutical applications

International audienc

Tight chalk: Characterization of the 3D pore network by FIB-SEM, towards the understanding of fluid transport

International audienceTight chalk intervals play a major role in North-Sea hydrocarbon fields, by controlling fluid flow pathways of hydrocarbon and water. Recent studies reveal that low-permeability chalk properties are dependent on clay content and cementation. Therefore, in this research, three characteristic samples were selected: (A) a porous micritic chalk, (B) a cemented chalk and (C) an argillaceous chalk. Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM) analyses were performed and 3D pore networks were reconstructed for each sample. By using MATLAB® and Avizo® softwares, relevant pore data were extracted, including pore volumes, lengths and network tortuosity. Results show that the pore length is reduced in tight chalks, with 140 nm on average in argillaceous chalk and 533 nm in cemented chalk, compared to 1091 nm in micritic reservoir chalk. Pore shape analysis demonstrates that, when present, clay flakes are predominant. Argillaceous chalk displays 35% of flattened pores, while these represent only 15 and 18% of pores in micritic and cemented chalk respectively. Virtual rock porosity calculated from FIB-SEM is consistent with helium porosity lab-measurements. MICP pore-throat diameters also match calculated pore widths. These preliminary findings confirm the potential of FIB-SEM analyses in characterizing chalks porous media. In order to understand fluid transport, fluid flow was simulated on each sample using the Lattice Boltzmann Method (LBM), which allows visualising fluid pathways and calculating permeabilities. Simple phase LBM-modelled permeabilities are on the same order of magnitude as gas permeabilities measured on centimetric plugs with Klinkenberg correction. This means that the pore network characterized by FIB-SEM has a significant contribution to macroscopic fluid transport. The impact of clay content and cementation degree on total porosity and pore shapes in chalk is a key finding, which requires to be accounted for, e.g. in mesoscale fluid flow modelling

Reduction of starch hydrophilicity by grafting lignin derivatives under EB irradiation: A study of model compounds

International audienc

Reduction of starch hydrophilicity by grafting lignin derivatives under EB irradiation: A study of model compounds

International audienc

Chapter 9: Reduction of starch hydrophilicity by grafting lignin derivatives under electron beam radiation: a study of model compounds

International audienc

Reduction of starch hydrophilicity by grafting lignin derivatives under EB irradiation: A study of model compounds

International audienc

Preparation and characterization of novel chitosan and beta-cyclodextrin polymer sponges for wound dressing applications

International audienceChitosan (CS) presents antibacterial, mucoadhesive and hemostatic properties and is an ideal candidate for wound dressing applications. This work reports the development of sponge-like materials obtained from physical hydrogels after the interaction between CS and a p-cyclodextrin polymer (PCD) in acidic conditions to provoke immediate gelation. Characterization consisted of zeta potential (ZP) measurements, rheology analysis, Fourier transform infrared (FTIR), Raman spectroscopy, wide angle Xray scattering (WAXS) and scanning electron microscopy (SEM). Swelling behavior, cytotoxicity, drug sorption and drug delivery properties of sponges were assessed. ZP indicated that CS and PCD presented opposite charges needed for physical crosslinking. Rheology, swelling, and cytotoxicity of sponges depended on their CS:PCD weight ratios. Increasing PCD in the mixture delayed the gel time, reduced the swelling and increased the cytotoxicity. FTIR and Raman confirmed the physical crosslinking between CS and PCD through ionic interactions, and WAXS showed the amorphous state of the sponges. Finally, the efficiency of chlorhexidine loaded sponge against S. aureus bacteria was proved for up to 30 days in agar diffusion tests

Multilayered textile coating based on a -cyclodextrin polyelectrolyte for the controlled release of drugs.

International audienceThe aim of this work was to develop the formation of multilayered coating incorporating a cyclodextrin polyelectrolyte onto a non-woven polyethylene terephthalate (PET) textile support in order to obtain reservoir and sustained release properties towards bioactive molecules. We optimized the multilayer assembly immobilization onto the PET surface according to the layer-by-layer (LbL) deposition process. After a pre-treatment of the textile support aiming to offer a sufficient ionic character to the surface, it was alternatively immersed into two polyelectrolytes aqueous solutions consisting of chitosan (CHT) as polycation on the one hand, and a _-cyclodextrin polymer (polyCTR- _CD) as polyanion on the other hand. In a second approach, a TBBA/polyCTR- _CD complex (4-tert-butylbenzoic acid, TBBA) was used in order to load the system with a drug model whose kinetics of release was assessed. Gravimetry, microscopy, OWLS, colorimetric titration, infrared and zetametry were used as characterization techniques. An effective deposition on the textile surface due to ionic interactions with alternation of up to 10 layers of each of both polyelectrolytes was clearly evidenced. However, we observed that layer formation occurred to a lesser extent when TBBA/polyCTR- _CD complex was applied instead of polyCTR- _CD alone. The release study showed that drug reservoir properties and release kinetics could be controlled by the number of layers in the system and that TBBA release was faster than the multilayered coating degradation