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Preparation of biopolymer aerogels using green solvents
Citation Link: https://doi.org/10.15480/882.1997
Publikationstyp
Journal Article
Publikationsdatum
2016-07-04
Sprache
English
Author
Institut
Enthalten in
Volume
2016
Issue
113
Start Page
e54116
Citation
Journal of Visualized Experiments 113 (2016): (2016-07-04)
Publisher DOI
Scopus ID
Publisher
[S.l.]
Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers (gelatin, agar, cellulose), only recently have biomasses been recognized as an abundant source of chemically diverse macromolecules for functional aerogel materials. Biopolymer aerogels (pectin, alginate, chitosan, cellulose, etc.) exhibit both specific inheritable functions of starting biopolymers and distinctive features of aerogels (80-99% porosity and specific surface up to 800 m2/g). This synergy of properties makes biopolymer aerogels promising candidates for a wide gamut of applications such as thermal insulation, tissue engineering and regenerative medicine, drug delivery systems, functional foods, catalysts, adsorbents and sensors. This work demonstrates the use of pressurized carbon dioxide (5 MPa) for the ionic cross linking of amidated pectin into hydrogels. Initially a biopolymer/salt dispersion is prepared in water. Under pressurized CO2 conditions, the pH of the biopolymer solution is lowered to 3 which releases the crosslinking cations from the salt to bind with the biopolymer yielding hydrogels. Solvent exchange to ethanol and further supercritical CO2 drying (10 - 12 MPa) yield aerogels. Obtained aerogels are ultra-porous with low density (as low as 0.02 g/cm3), high specific surface area (350 - 500 m2/g) and pore volume (3 - 7 cm3/g for pore sizes less than 150 nm).
Schlagworte
Chemistry
Issue 113
Biopolymers
aerogels
supercritical CO2 drying
green solvents
amidated pectin
hydrogels
DDC Class
620: Ingenieurwissenschaften
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