Properties of Freeze-Dried Gelatin/Clay Aerogel Composites Crosslinked with Tannic Acid

Polymer-based aerogels are tough, low-density, and thermally insulating materials currently receiving increasing attention. In this work, robust all-natural aerogel composites have been obtained by incorporating nanoscale montmorillonite and tannic acid into a gelatin matrix via freeze-drying. The prepared aerogels exhibited low densities, good compressive properties, and low thermal conductivities. The significant improvement in the thermomechanical properties results from the strong bonding between gelatin and tannic acid. Under fire, the systems exhibited excellent flame retardancy with reduced thermal degradation rate and cone calorimeter burning parameters. A straightforward surface treatment with polydimethylsiloxane gave the aerogels exceptional and durable superhydrophobicity. These multifunctional composite aerogels are considered promising eco-friendly alternatives to synthetic polymer-based foams.