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Submitted to: Green Chemistry
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/28/2013 Publication Date: 12/5/2013 Citation: Kenar, J.A., Eller, F.J., Felker, F.C., Jackson, M.A., Fanta, G.F. 2014. Starch aerogel beads obtained from inclusion complexes prepared from high amylose starch and sodium palmitate. Green Chemistry. 16(4):1921-1930. Interpretive Summary: This research used a newly developed starch material with unique gelling properties to prepare high performance solid starch beads having low density and large surface areas. Solids like these are referred to as starch aerogels and are lightweight highly porous materials. Although the prepared beads were only 3-6 mm in diameter, they had surface areas ranging between 313-362 square meters per gram. For comparison, the area of a tennis court is approximately 261 square meters. To the best of our knowledge, these starch aerogels represent a significant improvement over those reported to date. The basic knowledge presented by this work has importance to researchers working in this area and these starch materials may have potential applications as carriers for controlled release of nutraceutical and agrochemical compounds, adsorbents, catalyst supports, and as scaffolding for tissue engineering applications. Technical Abstract: Starch aerogels are a class of low density highly porous renewable materials currently prepared from retrograded starch gels and are of interest for their good surface area, porosity, biocompatibility, and biodegradability. Recently, we have reported on starches containing amylose-fatty acid salt helical inclusion complexes that are simply prepared by jet cooking amylose-containing starches and blending with sodium palmitate. Aqueous dispersions of these complexes form hydrogels upon pH change and were used to prepare their corresponding xerogels, cryogels, and aerogels. Supercritical carbon dioxide (SC-CO2) drying of the starch gels preserved the inherent structure of the gels and afforded aerogels having a macroporous nanoparticulate internal structure with fissures and crannies. Depressurization rates were examined in an effort to optimize aerogel properties and starch aerogels that had densities between 0.120-0.185 g cm^3^ and BET surface areas ranging between 313-362 m^2^ g^-1^ were prepared. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, and scanning electron microscopy (SEM), were used to characterize the aerogels. The corresponding xerogel and cryogel showed them to have inferior properties. This method provides a convenient alternative to prepare starch aerogels and eliminates many difficulties associated with starch gelatinization and retrogradation procedures that are currently used to prepare the prerequisite starch gels. |
