Synthesis And Properties Of Silicone Surfactants Via Thiol-Ene "Click" Reaction

Silicone surfactants are a group of novel special surfactants with hydrophobic chain based on silicon.Compared with hydrocarbon surfactants,silicone surfactants exhibit high surface activity,the ability of superspreading,non-toxicity and excellent thermal stability.So they were widely used in many fields,such as cosmetics,paint,textile,pesticide,biomedicine and petrochemical industry.Along with the exhaustion of the resources,sustainable development of society and economy has been the focus all over the world.And it requires more and more efficient,green,and easy synthesis surfactants.Therefore,it's of great significance to carry out the study about the synthesis,properties and applications of the novel silicone surfactants.Thiol-ene reaction is the most simple reaction among the metal-free "click" chemistry which is simple,efficient,high selectivity and can be initiated by the photo or heat easily.Furthermore,most of the alkenes and almost all of the sulfhydryl compounds could be used as reactants.So the thiol-ene "lick"reaction have shown enormous potentials in polymer,medicine,biochemistry,surface modification,nanometer materials.In this thesis,valuable explorations about the synthesis and properties of silicone surfacatants via thiol-ene "click" reaction have been carried out.The main contents are as follows:A novel and facile approach was developed to obtain two kinds of sodium carboxylate silicone surfactants(Si3SCOONa and Si4SCOONa)with different hydrophobic groups which were synthesized via thiol-ene "click" reaction.The surface activity and aggregation behavior of sodium carboxylate silicone surfactants in aqueous solution were investigated by electrical conductivity,surface tension,transmission electron microscopy(TEM)and dynamic light scattering(DLS).Si3SCOONa and Si4SCOONa can reduce the surface tension of water to approximately 20 mN m-1,which prove that they exhibit admirable surface activity.The difference of surface activity between two surfactants reveal that the stronger the hydrophobic groups of hydrophobic,the lower CMC and stronger surface activity they have.The electrical conductivity measurements in different temperatures showed that the counterion binding(?)values of Si4SCOONa increase with the increase of temperature.It's found by analyzing the thermodynamic parameters of micellization that the micellization of Si4SCOONa was spontaneous and entropy driven.The addition of organic salts and inorganic salts can lower the CMC and surface tension of Si4SCOONa in aqueous solution and the ability following the order NaCl<KCl;(CH3)4NBr<(C2H5)4NBr<(C3H7)4NBr.The TEM and DLS tests indicated that the Si4SCOONa in aqueous solution or salt solution formed spherical aggregates with different diameters when the concentration of the solution beyond the CMC.And it's more easier for the hydrolyzation of Si4SCOONa in aqueous solution than other silicone surfactants,because Si-O-Si bond isn't stable in slightly alkaline solution.Thiol-ene "dick" reaction were explored as a less-costly and efficient routes to the production of polyether silicone surfactants.poly[(mercaptopropyl)methylsiloxane]was first synthesized and then functionalized by vinyl polyether.The structures of theobtained products were thoroughly characterized by FT-IR,H1NMR.Obviously,this approach is more simple,efficient and economical than the method of hydrosilylation which was commonly used.