The Synthesis And Properties Research Of Nonionic Gemini Surfactants

Gemini or dimeric surfactants,which are made up of two single-chain surfactanesjoined by a spacer at or near the head group have gained much attention,as thesenovel surfactants have many unique properties that are superior to those of theirmonomers,such as remarkably low critical micelle concentrations（cmc）,much highefficiency.In regard to reducing surface tensions,unusual aggregation morphologiesand better wetting,solubilizing,and foaming properties,which make them potentiallyuseful in many applications.We use linear chain fatty acid， polyethylene glycol （PEG）， bromine，concentrated sulphuric acid，chlorinated and phenol，hydroquinone as the basicmaterial, synthesis a series of linear chain fatty acid polyethylene glycol kind ofnonionic Gemini surfactants18-600，18-4000，18-6000，16-6000，14-6000，12-6000，10-6000，8-6000through condensation reaction.（to18-600for example,18means thenumber of carbon atoms of fatty acid,600means the degree of polymerization,anaverage number, the degree of polymerization is different because of process）. Theseproducts were characterized by the infrared （IR）and nuclear magnetic resonance（NMR）methods synthetic.Suspended drops method to determine the surface tensionabout the above ion Gemini surfactant.Determined the court angle of ion Geminisurfactant by hypsometry and goniometry, and discussed some influencing factorsabout surface property, such as Ca²⁺、Mg²⁺, concentration of inorganic salt andethanol. In addition, experiments were performed on the emulsion ability and calciumsoap scattered ability of the product by simple experiment. Furthermore, the effect oftemperature on emulsification properties was discussed. Finally, test electricproperties of the solution and the factors of electric properties were discussed.The experimental results show that all the systhe sized eight kinds of ion Geminisurfactants have smaller CMC and lower γcmcand much higher surface properties,meanwhile, the aqueous solution of products are of good wetting ability. Inorganicsalt concentration affects less on surface tension, but Ca²⁺and Mg²⁺have more effect-ions surface tension, ethanol can quickly reduce surface tension, but do not makemuch effect on CMC, ethanol can change wetting ability of the product aqueous solution and make the contact angle smaller. Temperature do not affect emulsifiedability.