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

Abstract

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.

Interpenetrated Multinetwork Hybrid Aerogels by Layered Montmorillonite and One-Dimensional Hydroxyapatite Fibers for Heat and Fire Insulation

“…Currently, compared with 2D organic lamellar materials with poor temperature resistance and easy ablation affect their application under high temperature conditions, 2D inorganic lamellar materials have received wide attention due to their high temperature resistance properties and ablation resistance. , The layered montmorillonite (MMT), as a natural and abundant clay material with low intrinsic thermal conductivity, is also a good aerogel matrix material due to the weak van der Waals forces between the nanosheets that help it to exfoliate and thus obtain a large specific surface area . However, directly doping MMT into soluble polymer aerogels can effectively improve the mechanical and thermal properties through the formation of interconnecting networks between MMT and polymer chains. − One-dimensional hydroxyapatite nanowires with excellent flexibility, high melting point (∼1650 °C), and abundant HAP structures (including nanocrystals, nanorods, and nanowires) can be obtained through different preparation methods, which endow the composites with unique functions, such as the nanosized mechanical enhancement and inhibition of gas-phase heat conduction. Among them, nanowires, with smaller diameters and larger specific surface areas, have attracted much attention in the fields of bioscience and thermal insulation and flame retardancy …”