Hybrid alginate based aerogels by carbon dioxide induced gelation: novel technique for multiple applications

Publikationstyp
Journal Article
Date Issued
2015-05-15
Sprache
English
Author(s)
Subrahmanyam, Raman  
Gurikov, Pavel  
Smirnova, Irina  orcid-logo
Institut
Thermische Verfahrenstechnik V-8  
TORE-URI
http://hdl.handle.net/11420/3141
Journal
The journal of supercritical fluids  
Volume
106
Start Page
23
End Page
33
Citation
Journal of Supercritical Fluids (106): 23-33 (2015)
Publisher DOI
10.1016/j.supflu.2015.05.003
Scopus ID
2-s2.0-84929915143
Publisher
Elsevier Science
This paper presents a technique of manufacturing alginate-based hybrid aerogels. The technique involves mixing a second component (biopolymers or filler materials) in sodium alginate solution and crosslinking with carbonates of metals like calcium, strontium, cobalt, nickel, zinc and copper. Various biopolymers (lignin, starch, pectin, carrageenan, methyl and carboxymethyl cellulose, gellan gum, and gelatin), polymers (PVA, PEG, Pluronic P-123), inorganic (sodium silicate) and filler materials (titania and hydrophobic silica) were used as the second component. It is suggested to use pressurized carbon dioxide (5MPa) for gelation and supercritical CO2 drying (10-12MPa) to yield aerogels. Obtained aerogels are ultra-porous with low density (as low as 0.017g/cm3), high specific surface area (200-800m2/g) and pore volume (2.3-9.5cm3/g for pore sizes<150nm). Basic examples expressing the applicability of these aerogels are demonstrated such as in the field of thermal insulation (thermal conductivity in the range 18.5-21.6mW/mK). Extension of carbon dioxide gelation technique from metal-crosslinked alginate-based system to other biopolymers (cellulose and chitosan) is also demonstrated.
Subjects
Aerogels
Biopolymer
Alginate
Hybrid
Thermal insulation
Hydrogel
DDC Class
600: Technik
620: Ingenieurwissenschaften
More Funding Information
Support from DFG (project SM 82/13-1)