Natural albumin/tannin cellular foams

• Formulation of foams with albumin and condensed tannins in acid or alkaline conditions.
• Characterization of the microstructure, thermal conductivity, pH and compressive strength.
• Compression/springback cycles of elastic samples with different moisture content.

Albumin/tannin-based foams were prepared under alkaline or acid conditions by whipping up a water solution of a protein, egg albumin, mixed with a second water solution of condensed flavonoid tannins. Foam formulations with 4 different condensed tannin bark extracts and different relative proportions of protein and tannin were developed with a rapid foaming process where the protein has a double function: co-reagent and surfactant as well. Physical properties such as mechanical performance, thermal conductivity, and porous structure were characterised to identify the large potential of applications of these new cellular foams, fully bio-based and probable easier biodegradability. Moreover, some albumin-based foams were found to be completely flexible in certain conditions.