Stability Of Pickering Emulsion Based On Polymer Particles

Pickering emulsion is characterized by low amount of emulsifier,low toxicity and high stability,so it has great potential application value in papermaking,medicine,cosmetics,materials and sewage treatment.Polymer particle emulsifiers are favored by scientists due to their diverse types,easy to control structure,adjustable hydrophilic and hydrophobic properties,higher emulsification performance and environmental responsiveness.At present,most polymer particles reported in the literature are prepared by emulsion polymerization,precipitation polymerization and self-assembly of polymer in selective solvent.However,particle size and morphology prepared by emulsion polymerization and precipitation polymerization are relatively simple,the preparation process of self-assembly method is complex,post-treatment is difficult,and the concentration of dispersion solution is low.Polymerization induced self-assembly is a new method to prepare polymer nanomaterials.And it has obvious advantages,for example,one-pot preparation,simple operation,high solid content,especially in polymer particle size control.Therefore,in this paper,polymer nanoparticles with different particle sizes and hydrophilicity were prepared by polymerization induced self-assembly method and used as particle emulsifier to study the influence of the addition of crosslinking agents,particle concentration,particle size and hydrophilicity on the emulsification performance.We hope that by exploring simple and fast preparation methods of polymer particle emulsifier,and the influencing factors of stable polymer particle emulsifier Pickering emulsion,so as to further improve the emulsification mechanism of polymer particle emulsifier and provide guidance for the preparation of Pickering emulsion.First of all,we prepared macromolecular chain transfer agents m PEG-DMP by RAFT polymerization,amphiphilic polymer nanoparticles PEG-b-PHPMA by polymerization-induced self–assembly.And the polymer nanoparticles were characterized by nuclear magnetic resonance hydrogen spectroscopy(H~1 NMR),nano-laser particle size meter(DLS)and transmission electron microscope(TEM).The results showed that the polymer nanoparticles with different sizes of PEG-b-PHPMA were obtained by adjusting the concentration and feeding proportion of the reaction system,and the polymer particles with weaker hydrophilicity PGMA-b-PHPMA were obtained by changing the macromolecular chain transfer agent.Then,The resulting polymer particles were used as emulsifiers to prepare Pickering emulsion,and the emulsion was characterized by optical microscope,interfacial tensiometer and uv-vis spectrophotometer.The results show that:1)The formation of crosslinking structure is a necessary condition for preventing polymer particles from being dispersed into polymer chains in high shear to the successful configuration of Pickering emulsion;2)Increasing the concentration of polymer particles can make the distribution of emulsion particles more uniform and smaller;3)Compared with the large-particle emulsifier,the small-particle emulsifier has lower interfacial tension,can move to the oil-water interface more quickly and has higher adsorption efficiency,so that when used as the emulsifier,the emulsion particles obtained are smaller and more stable;4)Compared with PEG-b-PHPMA particles,the weak hydrophilic PGMA-b-PHPMA particles have lower interfacial tension,faster movement to the oil-water interface,higher adsorption efficiency,smaller latex particles and better emulsion stability;5)In the experiment of ibuprofen release,the release rate can be effectively adjusted by changing the p H of the system,and the release rate of Pickering emulsion is slower than that of pure oil phase,indicating that particles adsorbed at the oil-water interface play a certain blocking effect.