title: Pillaring effects in macroporous carrageenan-silica composite microspheres.
abstract: The impregnation of a carrageenan gel by a silica sol is an efficient method to form a composite material which can be conveniently activated by CO2 supercritical drying. The textural properties of the solids have been characterized by nitrogen adsorption-desorption at 77 K and their composition by thermogravimetric analysis and EDX microprobe. Morphology was examined by SEM. The silica-carrageenan composites present an open macroporous structure. Silica particles retained inside the gel behaved as pillars between the polysaccharide fibrils and form a stick-and-ball network. The stiffening of the carrageenan gel by silica prevented its shrinkage upon drying. The nature of the alkali cations affected the retention of silica particles inside the gel. In the absence of silica, carrageenan fibrils rearrange under supercritical drying and form an aerogel with cavities in the mesopore range.
authors.affiliation: Laboratoire de Matériaux Catalytiques et Catalyse en Chimie Organique, UMR 5618-CNRS-ENSCM-UM1, Institut C. Gerhardt, FR 1878, 8 rue de l'Ecole Normale, 34296 Montpellier cedex 5, France.
authors.forename: M
authors.initials: M
authors.lastname: Boissière
authors.forename: A
authors.initials: A
authors.lastname: Tourrette
authors.forename: J M
authors.initials: JM
authors.lastname: Devoisselle
authors.forename: F
authors.initials: F
authors.lastname: Di Renzo
authors.forename: F
authors.initials: F
authors.lastname: Quignard
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry; D002351:Carrageenan / Q000737:chemistry*; D002412:Cations; D005782:Gels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008673:Metals, Alkaline Earth / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D009584:Nitrogen / Q000737:chemistry; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D013818:Thermogravimetry
chemical_list: D001672:Biocompatible Materials; D002412:Cations; D005782:Gels; D008673:Metals, Alkaline Earth; D002245:Carbon Dioxide; D012822:Silicon Dioxide; D002351:Carrageenan; D009584:Nitrogen