Physicochemical Properties of Aqueous Film-Forming Foams Based on Short Fluorocarbon Surfactant-Graft Hydrophilic Functional Groups.

The key components of aqueous film foaming foam extinguishing agents are fluorocarbon surfactants. Due to their toxicity and bioaccumulation, long-chain fluorocarbon surfactants have limited application prospects. Therefore, it is of great significance to study short-chain fluorocarbon surfactants as substitutes. In this work, three short-chain fluorocarbon surfactants with various hydrophilic groups and corresponding fire extinguishing agents were prepared. The physical and chemical properties of a single system and mixed system of fluorocarbon surfactants, including surface activity, spreading property, foaming property, 25% drainage time, and AFFF fire extinguishing property, were studied. For the results of the mixed systems, it was found that the critical micelle concentrations did not exceed 3.97 mmol/L and the minimum surface tension did not exceed 17.21 mN/m. Fluorocarbon surfactant solutions spread effectively on the surface of all fuels. The foam expansion is greater than 7.2, and the shortest of all 25% drainage times is 3.31 min. The extinguishing time of AFFFs on several fuel fires does not exceed 55 s, and the shortest burn-back time is 15.08 min. Anyways, these results indicate that the grafted hydrophilic short-chain fluorocarbon surfactants have significant application prospects in AFFFs.