Zeta电位和界面膜强度对水包油乳状液稳定性影响

Effects of Strength of Interfacial Film and Zeta potential on Oil-inwater Emulsion Stability

通过对表面活性剂、聚合物溶液和煤油体系油水界面剪切黏度和油珠的Zeta电位的测定,考察了界面膜强度和Zeta电位对水包油乳状液稳定性的影响。在煤油、表面活性剂、聚合物聚丙烯酰胺(3530S)或其氧化降解聚合物体系中,含有3530S时,界面膜强度值最大,最大值大于0.10 mN/m,Zeta电位为-18.4 mV,绝对值最大,乳状液最稳定。结果表明,油水界面膜强度和油珠表面的Zeta电位对水包油乳状液稳定性影响较大。界面膜强度和Zeta电位绝对值较大时,乳状液最稳定;当界面膜强度相差不大时,Zeta电位绝对值大的乳状液较稳定,此时双电层对乳状液稳定性起主要作用;当Zeta电位相差不大时,界面膜强度大的乳状液较稳定,此时界面膜强度对乳状液稳定性起主要作用。研究还表明,机械或氧化降解后的聚合物体系,界面剪切黏度和Zeta电位绝对值变小,乳状液稳定性变差。

The effects of interfacial film＇s strength and Zeta potential on the stability of O/W emulsion have been investigated by measuring the interfacial shear viscosity, zeta potential and emulsion stability of a system with surfactant, polymer and kerosene. In the system of kerosene and OPE-100 with polymer 3530S or its degradation polymer, the maximum of interfacial shear viscosity is more than 0. 1 mN/m ; the zeta potential is - 18.4 mV. The stability of the emulsion is high. The results show that the stability of the O/W emulsion is mainly affected by both the strength of the interfacial film and the zeta potential of the oil droplets. The higher the interfacial film＇s strength and the zeta potential are, the higher the stability of the O/W emulsion is. At the same level of interfacial film＇s strength, the stability of the emulsion is dominated by the zeta potential. In this case, the stability of the O/W emulsion is enhanced by electric double layer. On the other hand, interfacial film＇s strength plays an important role in keeping the stability of the emulsion at the same level of zeta potential. The study also shows that the interfacial shear viscosity, zeta potential and stability of the emulsion are decreased after the polymer have been degradated both mechniacally and thermochamically.