新型孪尾Gemini两性离子表面活性剂应用性能

分别采用改进的Ross-Miles法及分水时间法,对3种新型孪尾Gemini两性离子表面活性剂(C8C8L3Sz、C8C8L4Sz和C10C8L3Sz)的泡沫性能及乳化性能进行了研究，并考察了表面活性剂浓度、分子结构和温度等对其的影响。 结果表明，该系列表面活性剂具有较好的泡沫性能，且随其浓度的增加，泡沫最大高度和半衰期均存在一个稳定值，疏水链越长，其起泡性能越差，泡沫稳定性越好；温度升高，起泡性能变好，泡沫稳定性变差；当表面活性剂浓度一定时，体系中加入低浓度的短链醇及无机盐均能提高泡沫的稳定性；C8C8L3Sz、C8C8L4Sz和C10C8L3Sz作乳化剂的最适宜的用量分别为6×10-4、6×10-4和4×10-4 mol/L，疏水基越长，乳化性能越好，而连接基对其影响较小；温度升高，乳化性能变差；当油相烷烃碳数相同时，环烷烃要比直连烷烃更易达到最佳乳化效果，但二者的乳状液稳定时间相当；对于油相烷烃碳数不同时，烷烃的碳链越长，乳状液的稳定性越差，乳化效果越不好。

Application Performance of New Twin-Tailed Zwitterionic Gemini Surfactants

The foaming and emulsifying properties of three new twin-tailed zwitterionic Gemini surfactants(C8C8L3Sz, C8C8L4Sz, C10C8L3Sz) were studied by modified Ross-Miles method and watershed-time method, respectively. The effects of the concentration of surfactants, molecular structure, and temperature were investigated. Experimental results show that the three surfactants all have good foaming properties, and their maximum foam heights and half-lives exist stable values under experimental concentration. The results show that the longer the hydrophobic chains, the worse the performance of their foaming and the better foam stability. In addition, temperature increasing can make foaming properties better and foam stability worse. The foam stability can be improved by adding either short-chain alcohols or inorganic salts. The most appropriate dosage of the emulsifiers of C8C8L3Sz, C8C8L4Sz and C10C8L3Sz is 6×10-4, 6×10-4 and 4×10-4 mol/L, respectively. It shows the longer the hydrophobic chains, the better the emulsifying properties, and the effects of spacers on emulsifying properties are little. The emulsifying properties become worse by increasing temperature. When the oil phase has the same carbon number, cycloalkanes achieve the best emulsifying effect more easily than straight chain alkanes, but the stable time of emulsion of the two is almost the same. For alkanes with different carbon number, the longer the carbon chains of alkanes, the worse the stability of the emulsion and the better the emulsifying properties.