Ridha Ben Salem, Younes Moussaoui, Najib Mnasri, Elimame Elaloui and Louis Charles de Menorval
Chemistry Department, Science Faculty of Sfax, University of Sfax, Tunisia
Abstract: The aerogels, prepared by drying with supercritical CO2, preserve the dispersion of the hydrocolloids from which they result. Aerogel conditioning of the chitosan makes it possible to prepare porous solids of significant specific surface. We describe in this work the synthesis and the characterization of the chitosan gel. We used the acetic acid (AcOH, pH = 4) as solvent what makes it possible to solubilize the chitosan because of ionization of the amino group in C2 of the D-glucosamine.
The prepared chitosan solution is injected into a gelling solution: sodium hydroxide or sodium dodecylsulphate.
- The increase in the chitosan concentration or the degree of acetylation (DA) of the chitosan, decreases the specific surface of the synthesized chitosan gel.
- Supercritical CO2 drying effectively makes it possible to preserve the volume of the spheres of gel and to have a more significant specific surface in comparison with evaporative drying.
- The specific surface of the obtained gel by using the sodium hydroxide as gelling solution is higher than that of gel by using the sodium dodecylsulphate.
Keywords: Chitosan, N-acetylation, aerogel, xerogels and specific surface.