Abstract : Condensed flavonoid tannin-based foams from quebracho tannin extract have been developed using a new method of expansion based on fire-fighting or tunneling foams, where a foam concentrate forms a stable liquid foam. This new mechanical method of expansion allows obtaining a solid porous material after curing and hardening at room temperature, through a liquid foam formed by a tannin resin and an aqueous solution of surfactant. The stability of the as-obtained liquid foam and the influence of the amount of catalyst are reported. The use of this new approach for preparing tannin-based rigid foams avoids the problem of shrinkage presented by many other formulations where physical or chemical foaming is employed. Non-ionic surfactants have also been used in the formulation to obtain smaller cells and improve the structure of the new material. Bulk density (0.069–0.080 g/cm3), mechanical (compressive strength of 0.034–0.13 MPa) and thermal (0.045–0.047 W m−1 K−1) properties and morphological appearance of the foams have been characterised and reported.
https://hal.univ-lorraine.fr/hal-03110764
Contributor : Hassan Ayatti <>
Submitted on : Thursday, January 14, 2021 - 7:06:46 PM Last modification on : Thursday, February 25, 2021 - 11:05:04 AM