title: Bionanocomposite foams based on the assembly of starch and alginate with sepiolite fibrous clay.
abstract: Bionanocomposite foams based on alginate, potato starch and the microfibrous clay mineral sepiolite as reinforcing filler were prepared by lyophilization. Spectroscopic techniques were applied in order to assess the interaction mechanism established between the inorganic fibers and the polysaccharide chains, which is established between the hydroxyl groups in the polysaccharide chains and the silanol groups at the external surface of the sepiolite fibers. The textural properties studied by means of mercury intrusion porosimetry, FE-SEM and X-ray microtomography, revealed a decrease in porosity as the sepiolite content increased. Mechanical properties were also determined for the studied foams, showing an increase in compression moduli from 7.3MPa in the foam without sepiolite to 29MPa in foams containing 10% starch, 40% sepiolite and 50% alginate. Horizontal burning tests were carried out for a preliminary evaluation of the role of the inorganic fibers on the fire resistance properties of the bionanocomposite foams, revealing that bionanocomposite foams with sepiolite content >25% behave as auto-extinguishable materials. Post-synthesis cross-linking with CaCl2was carried out in some of these samples, leading to an increase in the compression modulus up to 40MPa for the optimal composition.
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain. Electronic address: darder@icmm.csic.es.
authors.forename: Margarita
authors.initials: M
authors.lastname: Darder
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain.
authors.forename: Charlene Regina Santos
authors.initials: CRS
authors.lastname: Matos
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Aranda
authors.affiliation: Laboratório Nacional de Nanotecnologia (LNNano), CNPEM, Campinas, SP, Brazil.
authors.forename: Rubia Figueredo
authors.initials: RF
authors.lastname: Gouveia
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Ruiz-Hitzky
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry; D000077215:Clay; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D017633:Magnesium Silicates / Q000737:chemistry; D053761:Nanocomposites; D013213:Starch / Q000737:chemistry*
chemical_list: D000464:Alginates; D000538:Aluminum Silicates; D006603:Hexuronic Acids; D017633:Magnesium Silicates; D020723:Glucuronic Acid; D013213:Starch; C001671:magnesium trisilicate; D000077215:Clay
keywords: Alginate; Biofoams; Fire resistance; Macroporous composites; Sepiolite; Starch