The Synthesis Of Amphiphilic Polymer Containing P4VP Via RAFT Living Polymerization And Its Emulsion Property

In recent years, the self-assembly of amphiphilic polymers has attracted extensive attention from researchers. Micelles can absorb at the oil/water interface and form stable emulsions. Compared with classical particulate emulsifiers, micelles have better emulsifying efficiency and stimuli-responsiveness. As the structures of the emulsifiers have an influence on their performance, it is of great significance to study the structures of emulsifiers and the mechanism of emulsification.Based on this, a series of amphiphilic polymers containing P4 VP with different ratios between hydrophilic units and hydrophobic units were synthesized via RAFT living polymerization in this paper. The amphiphilic polymers could aggregate into micelles in the selective solvent(hexane). The micelles could be used as particulate emulsifiers to stabilize hexane/water emulsion. The impact of the external environment such as micelles concentration, temperature et al on its emulsion performance was studied systematically. The result shows that the micelles which aggregate in the selective solvent(hexane) can be used as a highly efficient emulsifier to stabilize hexane/water emulsion. Currently, there are only a handful of research groups using micelles as particulate emulsifiers to stabilize the emulsions. As the monomers are widely used in our daily life and the synthetic route is simple, it can be used in industry.First of all, using S-1-dodecyl-S’-(a,a’-dimethyl-a’’-acetic acid) trithiocarbonate(DDMAT) as the chain transfer agent and 4VP as the monomer, a series of amphiphilic polymers containing P4 VP with different ratios between hydrophilic units and hydrophobic units were synthesized via RAFT living polymerization. The polymer structures were characterized by 1H NMR and GPC. The results show that a series of amphiphilic polymers with different ratios between hydrophilic units and hydrophobic units were synthesized by controlling the reaction time of RAFT living polymerization.After that, the micelles which aggregate in the selective solvent(hexane) were uesd as particulate emulsifiers to stablize hexane/water emulsion. Micelle concentration, temperature, the proportion of hydrophilic units to hydrophobic units in the polymers, the volume fraction between oil and water phase, the composition of oil phase, the salt concentration of the water phase, the speed and time of homogenization were studied respectively. The results are as followings:(1) Compared with other conditions, stable emulsions can be obtained under the conditions as follows: 25℃ temperature, 0.4g/L micelle concentration in the oil phase, 1:1 volume fraction between oil and water phase, 4000 rpm speed of homogenization, 2min time of homogenization;(2) The proportion of hydrophilic units to hydrophobic units in the polymers can be adjusted by controlling the reaction time of RAFT living polymerization. And as a consequence, the hydrophilicity on the surface of micelles can be changed. And this can result in changing the stability of the emulsion.(3) Increasing the volume fraction between oil and water phase can enhance the stability of the emulsion and the micelles which aggregate in the selective solvent(hexane) can stabilize many oil phase.(4) It is benefinial to enhance the stability of emulsion by decreasing the salt concentration of the water phase.(5) It is conducive to enhance the stability of the emulsion by increasing the speed and time of homogenization.