Study on foam extinguishing agents based on hydrocarbon and perfluorinated branched short-chain fluorocarbon surfactants mixed system

Aqueous film-forming foam extinguishing agent (AFFF) plays an important role in fighting pool fires, but the environmental problems caused by them are also increasingly apparent. The key component of traditional AFFF is C8 fluorocarbon surfactant, which is harmful to the ecological environment and human health. In this paper, a perfluorinated branched short-chain fluorocarbon anionic surfactant with high surface activity, simple synthesis route and easy industrial scale-up was reported. The surface activity and aggregation behavior of the mixed solution of this fluorocarbon surfactant and cetyltrimethylammonium bromide (CTAB) were studied by surface tension meter and transmission electron microscope. The results showed that CTAB and anionic fluorocarbon surfactant had the significant synergistic effect, and many vesicles could be observed to nestle together at the concentration of 0.0406 mol/L. Subsequently, three environmental friendly AFFF formulations (F-1, F-2, F-3) were designed with the mixed system of this fluorocarbon surfactant, CTAB and dodecyl betaine (BS-12) as foaming agent. The foam properties confirmed that F-1 possessed excellent foam properties, the initial foam height h(0) was 115.34 mm, 25% drainage time was 182.4 s, extinguishing time was 31 s, and burn-back time was 720 s. This type of fire extinguishing agent had potential for fire protection applications.