Preparation And Characteristics Of Silicone Surfactant Based On The Thiol

Silicone surfactant is a kind of polymer containing both the hydrophobic groups and hydrophilic groups.These surfactants not only have superior surface activity and"ultra-extensibility" than alkane surfactants,but also have non-toxicity,softness,high temperature resistance due to the presence of Si-O band.With the development of silicone products,silicone surfactants also have a bright future in the application of the industry,and become an indispensable material in detergents,polyurethanes,coatings,and other industries.Thiol group is highly activity.In this article,we used terpene addition reaction,radical addition reaction,oxidation reaction to prepare several kinds of silicone surfactants.And we studied the properties of these silicone surfactants.In the first part,we used the vinyl polysiloxane to react with cysteine and the amino acid silicone surfactants were prepared successfully.The molecular weight and molecular structure were indicated with the FT-IR、NMR and GPC.The surface tension,conductivity,relaxation time and the fluorescence intensity were tested to indicate the ability of these surfactants.The results of these test measurements showed that these surfactants with different hydrophilic base content all had high surface activity.The minimum surface tension and the CMC declined with the hydrophilic base content increased.The minimum surface tension could reach 23mN/m.We also studied the aggregation behavior of these surfactants in the aqueous solution.The results indicated that it forms micelles in aqueous solution.The value of β is tiny which indicated that the volume of micelles is small.Its thermodynamic process is a spontaneous helium-driven process.The hydrophobic factor also declined when the hydrophilic base content decreased and the minimum is 1.1.In the second part,anionic surfactants with different carboxylic acid group contents and different molecular weights were synthesised via the radical addition reaction.The surface activity and aggregation behavior in aqueous solution were studied.These results indicated that these surfactants all had surface activity which reduced the surface tension of water to 21mN/m.The molecule weight had little effect on the surface activity.The value of CMC and the minimum surface tension continued to decline when the hydrophilic base content increased.The micellization is also a spontaneous helium-driven process.Thirdly,we studied the preparation procedure of sulfonic silicone surfacants using the oxidation of the thiol group.The results confrimed that it is difficult to conduct this reaction due to the heterogeneous reaction problem.We used the hydrogen peroxide solution and DMSO to oxidize the thiol respectively and we improved the procedure of the oxidation reactions.So we draw conclusions as following,the conversion rate could reach 40%when the thiol solved in the buffer solution reacted with the hydrogen peroxide solution at room temperature after 24h.The conversion rate could reach 30%when the thiol reacted with the DMSO.The best temperature for experiment is 90 ℃.The reaction should conduct about 7h with the presence moderate water and HBr.