Nitrogen sorption as a tool for the characterisation of polysaccharide aerogels

Supercritically dried aerogels of several polysaccharides (chitin, chitosan, alginate, alginic acid, κ-carrageenan, and agar) have been characterised by physisorption of N 2. Surface areas as high as 570 m 2 g −1 have been measured. The nature of the functional groups of the polysaccharide significa...

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Bibliographic Details
Published in:Carbohydrate polymers 2011-04, Vol.85 (1), p.44-53
Main Authors: Robitzer, M., Tourrette, A., Horga, R., Valentin, R., Boissière, M., Devoisselle, J.M., Di Renzo, F., Quignard, F.
Format: Article
Language:English
Subjects:
adsorption
Adsorption enthalpy
Aerogel
Agar
Alginate
alginates
Applied sciences
Carrageenan
Chemical Sciences
Chitin
Chitosan
Comparison plots
Condensed Matter
drying
enthalpy
Exact sciences and technology
hydrocolloids
kappa carrageenan
Material chemistry
Materials Science
Natural polymers
nitrogen
Physicochemistry of polymers
Physics
Physisorption
Polymers
Polysaccharides
solvents
Starch and polysaccharides
Supercritical drying
surface area
Surface polarity
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Summary:Supercritically dried aerogels of several polysaccharides (chitin, chitosan, alginate, alginic acid, κ-carrageenan, and agar) have been characterised by physisorption of N 2. Surface areas as high as 570 m 2 g −1 have been measured. The nature of the functional groups of the polysaccharide significantly influences the adsorption of N 2 on the surface of the aerogel. The net enthalpy of adsorption increases with the polarity of the surface groups of the polymer, in the order chitin < agar ≤ chitosan < carrageenan < alginic acid ∼ alginate. The surface area and the mesopore distribution of the aerogels depend both on the dispersion of the parent hydrogel and on the behaviour of each polymer in the drying treatment. Aerogels which retain the dispersion of the parent hydrogel are mainly macroporous (pores larger than 50 nm) while materials liable to shrink upon solvent exchange form mesoporous structures.
ISSN:0144-8617
1879-1344
DOI:10.1016/j.carbpol.2011.01.040