Investigations On Synthesis And Application Of Fluorocarbon Surfactants

Fluorocarbon surfactant is one of the most important surfactants, it has the highest surface activity up to the day. Another property of fluorocarbon surfactant is the excellent property of the mixtures of fluorocarbon surfactants and hydrocarbon surfactants. The mixtures have much higher surface activity.Aqueous film-forming foam fire fighter (AFFF) is a highly efficient fire fighter that has been widely used in fire fighting industry for extinguishing oil fire. AFFF contains mainly fluorocarbon and hydrocarbon surfactants, forming film on oil surface, and extinguishs fire by the film and foams.In this thesis new fluorocarbon surfactants were synthesized using oligo(hexafluoropropene oxide)—(HFPO)_n. Surface tension and critical micelle concentration(CMC) were studies as well as reat-proof stability and chemistry stability of new fluorocarbon surfactants. The experiment results revealed that the surface properties of new fluorocarbon surfactants are sharply better compared with the other surfactants. Also the spreading properties on the surface of cyclohexane were investigated, dates indicate that non-ionic fluorocarbon surfactant has satisfied spreading rates.The mixtures of non-ionic fluorovarbon surfactant, SDBS and SDS were investigated which have predominant properties than single surfactant. Especially the surface tension of combined surfactants was 18.1mN/m and interface tension is 1.7～2.0mN/m. Meanwhile the combined surfactants could reduce the quantity of the fluorocarbon surfactant effectively and spread fast on oils.On the basis of the fire fighting principle of AFFF, the fire fighting performance of AFFF was evaluated by indoor method using spreading coefficient, expansion ratio, foam drainage time, and so on. The interactions of combined surfactant with various additive agents were also investigated. The suitable additives and concentration were screened out, and aqueous film-forming foam fire extinguishing agent with low cost and good fire extinguishing performance was developed. The new products passed the test of Fixed Extinguishing System. The test result indicated that all the targets of the product achieved the requests of the national criterion—GB17427-1998 aqueous film-forming foam fire extinguishing agents.