Application Of Quaternary Ammonium Fluorocarbon Surfactant In AFFF

To prevent the environment from being destroyed by fluorochemicals of the AFFF,it has been a hot research topic in the field of international fire sciences to find out those substitutes from signature of Stockholm Convention.Based on this consideration,an efficient and environment-friendly quaternary ammonium fluorocarbon surfactant was synthesized.Then this paper designed and evaluated the performance of AFFF formula.The main work is as follows:（1）A quaternary ammonium cationic fluorocarbon surfactant was successfully synthesized using D2 as starting material and getting its structure by of IR、NMR and HRMS.Then the relevant performances were investigated.The research results showed that the synthesis method of the fluorocarbon surfactant was simple,and easy to operate,the fluorocarbon surfactant had the very good surface activity,lower critical micelle concentration(cmc is 9.2×10^-4 mol/L)and lower critical surface tension（γcmc is 20.29mN/m）;（2）AFFF was prepared around fluorocarbon surfactant after the other components in the fire extinguishing agent were screened.And then We determined the physical and chemical properties and fire-fighting performance of AFFF solution.The results of the experiment showed that the physical and chemical properties of AFFF solution have reached or closed to the national standards.The AFFF solution spreaded slowly in the ethane surface with the surface tension was 21.9mN/m.It had excellent foam properties,but drainage time of foam is too short.The AFFF solution had a long extinguishing time（156s）and a short burnback time（350s）,far below the national standard（600s）.（3）The formulation of the AFFF was optimized.It was found that the quaternary ammonium fluorocarbon surfactant had the best synergistic effect with octane sulfonate-APG0810.The surface tension of the composite system decreased from 20.29mN/m to 19.75mN/m.At the same time,according to the laboratory evaluation methods such as surface tension,foaming ratio and 25%draining time,the optimum amount of other additives was screened out.Finally,the foam solution was prepared and evaluated for physical,chemical properties and fire-extinguishing performance.The results showed that the physical and chemical properties of optimized AFFF solution had reached the requirements of national standards.The AFFF solution spreaded rapidly in the ethane surface with the surface tension was 20.1mN/m.The AFFF solution had a short extinguishing time（57s）and a longer burnback time（13min23s）.According to the standard GB 15308-2006,the AFFF reached Class III C.In summary,the AFFF designed in this paper can be used as a substitute of perfluorooctyl-based AFFF.