Highly mesoporous organic aerogels derived from soy and tannin

The first organic aerogels natural at the 91% level, based on soy and tannin, are reported. Such materials were prepared from denatured soy protein which was formylated, crosslinked with flavonoid tannin at different pHs, gelled and cured at 85 degrees C, and finally dried with supercritical CO2. The resultant aerogels presented both low bulk density and high mesopore volumes. Morphology, pore texture, chemical structure and thermal performances have been investigated by SEM, envelope and helium pycnometry, nitrogen adsorption at 77 K, FTIR, elemental analysis, XPS, NMR and hot disk transient plane source methods, respectively. We show that soy-tannin aerogels are among the "greenest" organic aerogels combining low cost, renewable character, highly developed mesopore texture and good thermal performances.