Bioactive glass hybrid scaffolds with well-controlled and opened porosity: Gelatin/SiO2-CaO System.

International audienc

Bioactive glass hybrid scaffolds with well-controlled and opened porosity: Gelatin/SiO2-CaO System.

International audienc

Bioactive glass hybrid scaffolds with well-controlled and opened porosity:Gelatin/SiO2-CaO System.

International audienc

Investigation of calcium incorporation and organic–inorganic covalent linking in bioactive glass–gelatin hybrids.

International audienc

Bioactive glass hybrid scaffolds with well-controlled and opened porosity:Gelatin/SiO2-CaO System.

International audienc

Investigation of calcium incorporation and organic–inorganic covalent linking in bioactive glass–gelatin hybrids.

International audienc

Alkylation of thiophenic compounds over heteropoly acid H3PW12O40 supported on MgF2

International audienceThe alkylation of sulfur-containing compounds (benzothiophene and thiophene) with 2-methyl-1-pentene was investigated over MgF2-supported heteropoly acid (H3PW12O40: HPW) as catalysts under mild conditions (85 degrees C, atmospheric pressure). The magnesium fluoride used as support was prepared by a sal-gel method and exhibited a high specific surface area (186 m(2) g(-1)). Several solids containing various amounts of HPW (in the range of 5 wt% to 46 wt%) were prepared by incipient wetness impregnation and fully characterized (ICP-OES, XRD, N-2 adsorption, TEM, IR, adsorption of pyridine followed by IR, F-19 and P-31 MAS NMR). For all solids, it was observed that the Keggin structure of HPW was preserved and that the heteropoly acid was finely dispersed on the MgF2 support. A significant modification of the textural properties of the sample containing the higher amount of HPW (46 wt%) was observed and attributed to a pore blocking phenomenon by HPW. As expected, the HPW loading in the range of 5-30 wt% allowed an increase of the Bronsted acidity. Whatever the catalyst, benzothiophene was only transformed by mono-alkylation, whereas the olefin underwent alkylation, oligomerization and isomerization, the latter being largely predominant and yielded 2-methyl-2-pentene. The increase of the HPW loading until 30 wt% led to an increase of the catalytic activity, the selectivity being not modified. In addition, a significant deactivation of catalysts containing 30 wt% and 40 wt% of HPW was observed and attributed to a strong adsorption of the alkylated products. Thiophene presented a poor reactivity through alkylation compared to benzothiophene

Quantitative mineralogical mapping of hydrated low pH concrete

International audienc

Characterization , acidity and catalytic activity of Ga-SBA-15 materials prepared following differentsynthesis procedures

Incorporation or grafting of gallium atoms in/on mesoporous SBA-15 silicas was carried out using four different procedures. The structure and texture of the materials obtained were characterised by classical methods (X-ray diffraction, TEM, porosimetry measurements, XPS, 71Ga NMR spectroscopy). Acidity of the solids was evaluated by ammonia adsorption, TPD of this gas and FTIR spectroscopy of adsorbed probes (2,6-dimethylpyridine and deuterated acetonitrile). Catalytic activity was tested first in the isomerisation of a-pinene and second in the oxidative cleavage of cyclohexene oxide. In this latter case, the results are compared with those obtained in the presence of Al-SBA-15 catalysts prepd. under similar conditions

Polycaprolactone / bioactive glass hybrid scaffolds with controlled porosity

International audienceInorganic-organic hybrids appear as promising bone substitutes since they associate the bone mineral forming ability of bioactive glasses (BG) with the toughness of polymers. In such hybrids, the main challenge concerns the incorporation of calcium into the BG silicate network, which plays a major role in biomineralisation. Hybrids comprised of polycaprolactone (PCL, M n = 80,000 g/mol) and SiO 2-CaO BG were produced by a sol-gel process and built into porous scaffolds with controlled pore and interconnection sizes. PCL was chosen as the polymer because its slow degradation in vivo makes it a suitable candidate for bone filling. The calcium incorporation, apatite-forming ability, mechanical properties and degradation rate of the hybrid scaffolds were evaluated