Thermal stability of gel foams co-stabilized by nano-aluminum hydroxide and surfactants

Foam stabilized by nanoparticles and surfactants demonstrates potential in developing environmentally friendly foam extinguishing agent for liquid fuel fire. However, many properties on foams must be investigated first before application. The present study focuses on thermal stability of gel foams co-stabilized by nanoparticles and surfactants. Nano-aluminum hydroxide (nano-ATH), short-chain fluorocarbon surfactant (FS-50), and hydrocarbon surfactant (APG-0810) were selected to prepare foam dispersions. Surface activity, viscosity, conductivity, and foamability were characterized. Foam coarsening, drainage, and decay process under high temperature were systematically analyzed. Results indicate that the surface activity and conductivity of nano-ATH/FS-50/APG-0810 dispersions decrease gradually, but the viscosity increases with increasing nano-ATH concentration. The foamability of the dispersions decreases with addition of nano-ATHs and slightly increases with increasing nano-ATH concentration. The viscosity of foam dispersions increases sharply, foamability shows an apparently increase, and foam flowability decreases upon nano-ATH concentration is above 5%. Foam coarsening, drainage, and height decay decrease with increasing nano-ATH concentration. Foam thermal stability under 200°C is enhanced with increasing nano-ATH concentration. These findings can provide a reliable theoretical basis for the application of nano-ATH in developing fire extinguishing agents for liquid fuel fires.