Mechanism of PFOS-free Short-chain Fluorocarbon Surfactants in Water-based Fire Extinguishing Agents
#Company News ·2026-06-15 22:12:50
1. Mechanism of Interfacial Tension Reduction (Core Function)
Molecules of short-chain fluorocarbon surfactants contain both fluorocarbon hydrophobic and oleophobic terminals as well as hydrophilic polar terminals, which can be directionally adsorbed at the two-phase interface between water and oil. Compared with conventional hydrocarbon surfactants, they exhibit stronger surface activity and can reduce the surface tension of fire extinguishing agent aqueous solutions to below 22 mN/m.
The low surface tension endows the fire extinguishing liquid with excellent spreading capacity, enabling it to spread rapidly and evenly on the surface of flammable liquids such as gasoline, overcoming the surface resistance of liquids and laying a foundation for water film formation. This is also the key factor allowing Aqueous Film-Forming Foam (AFFF) agents to achieve rapid coverage.
2. Mechanism of Flame Retardancy via Water Film Isolation
As an amphoteric fluorocarbon system, 1158 short-chain fluorocarbon surfactant molecules form a continuous and dense hydrophobic barrier water film on the oil surface. Tightly covering the burning liquid surface, the water film serves two functions: first, it blocks contact between air and flammable vapor to cut off the oxygen required for combustion; second, it restrains oil volatilization and reduces the continuous release of flammable vapor, curbing fire spread at the source.
With strong adhesion and resistance to flame damage, this water film differs from ordinary foam that only provides physical coverage. It delivers dual flame retardant effects of oxygen isolation and vapor suppression, effectively accelerating fire extinguishing.
3. Mechanism of Foam Synergism and Stabilization
This system adopts a compounded formula of fluorocarbon and hydrocarbon surfactants to build a synergistic efficiency system:Short-chain fluorocarbon surfactants optimize interfacial properties and enhance spreadability; anionic SDS and nonionic APG0810 hydrocarbon surfactants dominate foaming to generate high-expansion foam. Fluorocarbon molecules intersperse within foam liquid films to boost the toughness and strength of the films. Combined with the xanthan gum and triethanolamine foam stabilization system, the foam drainage time is extended by 25%, preventing rapid foam collapse.
The stable foam layer overlaid on the underlying barrier water film creates a double-layer protective structure of "foam coverage + water film sealing", which greatly improves heat resistance and burnback resistance.
4. Mechanism of System Stability, Temperature Resistance and Freeze Resistance
Amphoteric short-chain fluorocarbon molecules feature mild ionic properties and maintain stable chemical properties within the neutral pH range of 6.5 to 8.0. Matched with a sodium dihydrogen phosphate buffer system, they inhibit the hydrolysis of surfactants. Meanwhile, their molecular structure is compatible with polyol solubilizing systems (ethylene glycol, n-butanol) and shows excellent compatibility with various additives:
Low-temperature environments: Molecules rarely agglomerate or precipitate, ensuring no delamination or sedimentation at -20°C;
Normal/high-temperature storage: Molecular degradation and microbial growth are unlikely to occur. With the addition of EDTA disodium salt and sodium benzoate, the overall shelf life of the product is extended to more than 2 years.
5. Environmental Adaptation Mechanism (Core Advantage of PFOS-Free Formula)
Traditional long-chain fluorocarbon surfactants contain PFOS/PFOA, featuring long carbon-fluorine chains and excessively high chemical stability that renders them hard to biodegrade naturally. The PFOS-free short-chain fluorocarbon structure adopted here shortens the carbon-fluorine segments. While retaining high surface activity, its molecules can be degraded by the natural environment with a biodegradation rate of over 60%. It delivers reliable fire protection performance while avoiding risks associated with persistent organic pollutants, balancing environmental friendliness and functional performance.
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