Synthesis,Activities And Application Of Fluorinated Surfactants

Surfactants of PFOA and PFOS have poor degradability and are difficult to synthesize.Therefore,it is necessary to look for low-cost and simple process to develop novel structural fluorinated surfactants and also to evaluate their biodegradability and effect on the environment.Introducing branch is one of effective strategies for synthesizing non-bioaccumulable alternatives.Oligomerization of hexafluoropropylene(HFP)is the main method for preparing fluorinated branch.At present,fluorinated surfactants derived from perfluoro-2-methyl-2-pentene(D2)have few categories and excellent performance.In view of this,develop novel fluorinated surfactants derived from D2 has great significance.In this article,we synthesized of several novel kinds of fluorinated surfactants from D2,measured their performance and found the relationship between their structure and properties.We also synthesized of several fluoropolymers from HFP.The application of compounds with high performance in aqueous film-forming foam extinguishing agent and modification of substrate's surface was investigated.A fluorinated phosphonate anion surfactant containing CF3CF2CF2C(CF3)2-group was successfully synthesized using D2 as starting material.All the steps were 'easy work-up and mild reaction conditions.The surfactant exhibited excellent surface activity,that is,the cmc.value was about 1.5×10-2 mol/L and the surface tension of water was 19.2 mN/m at the cmc.However,the surfactant had carcinogenic potential.Novel branched fluorinated cationic(FCS),gemini,amphoteric surfactants and carboxylic acid of lithium,sodium and potassium salts containing CF3CF2CF2C(CF3)2-group were successfully synthesized using D2 as starting material.All the values of surface activities of the six novel surfactants were lower than that of sodium perfluorooctanoate.FCS had low toxicity and was non-carcinogenic.Performance of the complex system of potassium salt and APG0810 were investigated.The amount of potassium salt can be reduced by 100 times without substantially changing the surface tension.The interfacial tension of the potassium salt aqueous solution and cyclohexane could be greatly reduced when APG0810 was added.The complex aqueous solution could spread on the surface of cyclohexane rapidly when the mass ratio of potassium salt and APG0810 was 1:5 and the concentration of potassium salt was 3.29×10-3 mol/L,and three minutes were needed to ignite the cyclohexane solution when the spread amount of the mixed aqueous solution was about 40?L,indicating that the complex system had good fire fighting capability.Novel branched fluorinated sulfonate cationic,gemini and amphoteric surfactants were prepared,they all had low solubility in water and exhibited poor ability to reduce the surface tension of water.A series of branched fluorinated nonionic surfactants with different length of hydrophilic chains were synthesized,their solubility became larger with the increase of the chain length.But,the surface tension measurement results showed that their ability and efficiency to reduce the surface tension of water changed little when the value of n was equal to or greater than 4.All the values of surface activities of the novel nonionic surfactants were lower than that of sodium perfluorooctanoate.Cloth dealed with 0.01 equivalent of the intermediate had excellent water repellence and poor oil repellency when using DMAP as catalyst and Et3N as acid scavenger.Fluorine-containing benzene sulfonic acid surfactant was synthesized,the surfactant exhibited excellent ability to reduce the surface tension of water.Besides,it had good salt-resistance.A novel fluorine-containing unsaturated monomer was synthesized from hexafluoropropylene.Homopolymer of the monomer and copolymers of the monomer and butyl methacrylate were successfully prepared.The homopolymer had excellent repellency properties which were worse than that of polymers containing C7F17-moieties but better than that of polymers containing C6F13-moieties.We found that the water repellency decreased significantly when the fluorine content was less than 10 wt%while the oil repellency decreased obviously when the fluorine content was less than 15 wt%.The surface roughness played a significant role in surface activities,the increase of surface roughness led to smaller contact angle hysteresis.The amount of butyl methacrylate in the copolymer had no effect on the thermal stability of the copolymer.All the polymers had similar thermal stability and the decomposition temperatures were all above 200?.On the basis of all these encouraging results,we believe that preparing branched fluorinated surfactants using D2 will be one of the most environmentally friendly and economical method for synthesis of alternatives to PFOA and PFOS.