Silica Foams for Fire Prevention and Firefighting.
We report the new development of fire-extinguishing agents employing the latest technology of fighting and preventing fires. The in situ technology of fighting fires and explosions involves using large-scale ultrafast-gelated foams, which possess new properties and unique characteristics, in particular, exceptional thermal stability, mechanical durability, and full biocompatibility. We provide a detailed description of the physicochemical processes of silica foam formation at the molecular level and functional comparison with current fire-extinguishing and fire-fighting agents. The new method allows to produce controllable gelation silica hybrid foams in the range from 2 to 30 s up to 100 Pa·s viscosity. Chemical structure and hierarchical morphology obtained by scanning electron microscopy and transmission electron microscopy images develop thermal insulation capabilities of the foams, reaching a specific heat value of more than 2.5 kJ/(kg·°C). The produced foam consists of organized silica nanoparticles as determined by X-ray photoelectron spectroscopy and X-ray diffraction analysis with a narrow particle size distribution of ∼10-20 nm. As a result of fire-extinguishing tests, it is shown that the extinguishing efficiency exhibited by silica-based sol-gel foams is almost 50 times higher than that for ordinary water and 15 times better than that for state-of-the-art firefighting agent aqueous film forming foam. The biodegradation index determined by the time of the induction period was only 3 d, while even for conventional foaming agents this index is several times higher.
ITMO University , St. Petersburg, Russia.
Alexander V
AV
Vinogradov
JSC NPO "SOPOT" , St. Petersburg, Russia.
D S
DS
Kuprin
Bauman MSTU , Moscow, Russia.
I M
IM
Abduragimov
JSC NPO "SOPOT" , St. Petersburg, Russia.
G N
GN
Kuprin
JSC ≪IVHIMPROM≫ , Ivanovo, Russia.
Evgeniy
E
Serebriyakov
ITMO University , St. Petersburg, Russia.
Vladimir V
VV
Vinogradov
AFFF; fire; foam; silica; sol−gel