| Fluorocarbon surfactant is an important surfactant, which has unique properties: high surface activity, great heat resistant, chemical resistant, water proof and oil repellent. They are widely used in detergent, cosmetic, food, rubber, plastic, photosensitive materials and oil industries. Fluorocarbon surfactants enlarge the application fields of surfactants as they can be used in fields which hydrocarbon surfactants can not be qualified.In this paper, a series of fluorocarbon surfactants was synthesized and their surface properties, critical micelle concentration, the proper patterns of the surfactant molecules at the air/liquid interface, heat resistant, decontamination capability and inhibition capability were studied. At the end, the application of surfactants in polyurethane was investigated.Firstly, four fluorocarbon surfactants: CF3CF2CF2OCF(CF3)CF2OCF(C- F3)COOCnH2n+1, n=8, 12, 16, 18, were synthesized and their structures were characterized by UV, FT-IR and NMR methods. Their HLB values were tested.The surface tensions of the surfactants were here tested by Platinum Plate Method. And the surface tensions of the surfactants in commonly used organic solvents were also tested by the same method. The fluorocarbon surfactants can reduce the surface tension of many organic solvents to 40%～80% of that of their own. The critical micelle concentration (cmc) in organic cyclohexane was measured by the same method and the saturated adsorption and effective cross-section area were calculated. The proper patterns of the surfactants at the air/liquid interface were given.The thermal stability of the surfactants were excellent, as shown from the thermogravity curves, especially for the CF3CF2CF2OCF(CF3)CF2OCF- (CF3)COOC16H33 and CF3CF2CF2OCF(CF3)CF2OCF(CF3)COOC18H37, which can be stable under 200℃.The decontamination capability of the surfactant was studied by electric conductivity method. Compared with hydrocarbon surfactants, fluorocarbon surfactants showed great advantages here. Besides, the inhibition capability of the fluorocarbon surfactant was also distinguishing.The application of the fluorocarbon surfactants on polyurethane was studied. Results indicated when the concentration of the four kinds of fluorocarbon surfactants reached 1% in polyurethane membrane, the contact angle of water towards polyurethane improved by 8.8°,9.0°,11.4°,16.6°, respectively, which showed that the fluorocarbon surfactants can improve the water resistant property of polyurethane obviously. |
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