Starch Aerogels: A Member of the Family of Thermal Superinsulating Materials

Abstract

Starch aerogels were prepared via dissolution in water (thermomechanical treatment), retrogradation, solvent exchange, and drying with supercritical CO₂. Amylose content in starches was varied from 0 to 100%. The aerogels' bulk density, morphology, specific surface area, thermal conductivity, and mechanical properties under compression were investigated. Pea starch aerogels had one of the highest specific surface area and lowest density and thermal conductivity (0.021-0.023 W/m·K), with the latter indicating that a new thermal superinsulation material was obtained. A detailed study of the influence of processing parameters on pea starch aerogels properties showed the importance of retrogradation time which decreases specific surface area and increases mechanical properties and thermal conductivity. Finally, a comparison of starch aerogel thermal conductivity with that of other bioaerogels is performed.