Preparation And Stability Of Two Kinds Of Functional Emulsion

Emulsions could be divided into two groups. One is water-in-oil (W/O in brief) emulsion, the other is oil-in-water (O/W in brief). In this dissertation, the research is focused on the preparation and stability of emulsified SBS O/W adhesive and petroleum ether W/O emulsion.The preparation methods of these two kinds of emulsion are the same. Firstly, a surfactant is dispersed into oil phase, and then the blending is emulsified with an emulsifier. During the preparation process, the effect of emulsifying time, stirring rate, dose of surfactant and water content on the stability of the emulsions were studied. It is obvious that the ratio of water and oil, the type and the molecular structure of surfactant are the two key factors. Whilst the microscope was used to observe emulsions directly, it shows that the diameter of dispersed phase is resulted from stirring rate mainly. The stability of emulsion is higher when the droplet diameter of inner phase becomes more even and smaller.An environment-friendly emulsified SBS adhesive existing in the form of O/W emulsion was studied, SBS thermoplastic elastomer as the main material, rosin as the viscosity increaser, cyclohexane as the solvent and OP-10 as the emulsifier. The hydrophile polymer PVA was found to improve the stability and adhesive properties of this kind of emulsion adhesive. Furthermore, simple application was made with this new kind of adhesive, which showed that its adhesive strength was enough for adhesion of paper and plastic film.In the research of W/O petroleum ether emulsion system, the swelling and leakage of emulsion liquid membrane were studied, which was made by dispersing the emulsion into external phase twice. As a result, the swelling is about 20 percent and the leakage rate is very small, less than 3 percent. Furthermore, one can draw the conclusion according to the experimental phenomena that emulsion with high viscosity is not adapted to prepare for liquid membrane.Demulsification, which is relative to the emulsion stability, has been studied by three methods, including freezing/thawing, ultrasonic wave and centrifuging settlement. The freezing/thawing method is the best among of them, which has a demulsification ratio of above 95 percent at most cases. On the other hand, it is safe and needs nothing to add to the emulsion system. In practice, although freezing/thawing method has been practiced and studied well for the O/W emulsion system, it is new to use in the W/O emulsion system. In this dissertation, freezing/thawing method has been first time provided to treat six normal W/O emulsions with good results.