Preparation and properties of a fluorine-free aerogel foam extinguishing agent

Research on fluorine-free firefighting foams is urgently needed due to the environmental hazards of conventional aqueous film-forming foams. Functional particles have significant research potential in the development of fluorine-free foam extinguishing agents. In this study, hydrophobic aerogel particles were prepared using a template method, and a fluorine-free aerogel foam extinguishing agent was developed by electrostatic and steric stabilization. The research investigated the impact of aerogel particles and polymers (xanthan gum and polyethylene glycol) on foam characteristics, fire extinguishing performance, as well as their synergistic effect. The results indicated that polymers and aerogel particles reduced the average foam radius and enhanced the foam liquid film strength, though they could not inhibit foam coarsening. Although accelerating foam drainage, aerogel particles effectively enhanced the fire extinguishing performance of the foam. With the addition of only 0.4 wt% aerogel particles, the fire extinguishing time of the foam was reduced by 21.7 %, while 100 % burnback time increased by 45 %. Furthermore, the polymer enhanced the burnback performance of the foam in synergy with aerogel particles by improving foam stability on the hot heptane surface.