Study On Pickering Emulsion And Application Stabilized By Magadiite

The new functional nanoparticle materials and their stable Pickering emulsion have attracted great attention in many fields.Layered clay particles are a class of inorganic solid mineral materials.They are aboundant in resource reserves and are one of the cheap and environmental friendly mineral resources.Until now,the potential value of clay resources in emulsion emulsification technology has not been fully exploited and utilized.Lamellar material magadiite has been widely studied by researchers due to its unique lamellar structure,good structure modification property and biocompatibility.In order to realize the functional application of magadiite in various fields,it is of great significance and practical value to modify the magadiite and explore its application in the field of Pickering emulsion.In this thesis,magadiite was modified with cetyltriphenylphosphonium bromide,followed by the first stable preparation of Pickering emulsion with modified organic magadiite(Org-Mag)with suitable contact angle.The Pickering emulsion with oil concentration of 0.05wt% was stably prepared.The effects of solid particle concentration,oil-water ratio and pH on the stability of the prepared emulsion were investigated.It was found that as the concentration of solid particles increases,the emulsion layering stability increases firstly and then remains unchanged.When the particle concentration was increased to 0.3wt%,although the emulsion stabilization time was prolonged,the oil yield of the emulsion began to increase.Increasing the oil phase volume fraction can improve the delamination stability of the emulsion.The fixed particle concentration is 0.1% by weight,when the oil phase volume fraction is 0.5~0.66,the emulsion layering stability is better,when the oil phase volume fraction is greater than or equal to 0.66,the type of emulsion changes phase from oil-in-water to oil-in-water.When the fixed particle concentration is 0.5wt% and the ratio of oil to water is 1:1,a relatively stable pickering emulsion can be prepared by changing the pH value.When the pH value is at 4~9,the size of the droplets varies within a relatively small range.However,at different p H values,the particle size of the emulsion is basically the same and the particle size distribution is narrow.For the first time,Org-Mag was used as an emulsifier instead of the traditional surfactant,and Org-Mag/PMMA nanocomposite microspheres were prepared by Pickering emulsion method.The effects of oil-water ratio,emulsifier content and pH on the morphology of nano-composite microspheres were explored,and the products were characterized by XRD,FT-IR,SEM and TG.The results show that the wettability of the solid particles plays a key role in the successful preparation of the oil-in-water Pickering emulsion,and the Org-Mag/PMMA nanocomposite microspheres can be successfully prepared by Pickering emulsion polymerization,the thermal stability of polymer increased.If the ratio of oil to water is too high or too low,the normalization of emulsion polymerization will change and even explosion will occur.The concentration of solid particles will mainly affect the particle size distribution of the composite microspheres,when the concentration of solid particles is 3wt%,composite microspheres with uniform particle size distribution are prepared.The pH value mainly affects the particle size of the composite microspheres,within the pH range of 4~9,the particle size increases first and then decreases with the increase of the pH value.For the first time,Org-Mag/sodium alginate(Org-Mag/SA)nanohybrid drug carriers were prepared with Org-Mag synergistic sodium alginate by Pickering emulsion evaporation method.The effect of drug carriers with different content of Org-Mag on the sustained release of metronidazole was studied.The results show that Org-Mag with different content(90%,87.5%,83%,75%,50%,25%,12.5% and 10%)can successfully prepare drug carriers by emulsion evaporation method,and the drug carriers have a sustained release effect for metronidazole,metronidazole get into the carrier materials through the physical apparent adsorption,electrostatic interaction,coating and other mechanisms.The drug carriers prepared with different Org-Mag content had a greater effect on the sustained release of metronidazole,and there were two main phases of release,0~4 h for faster release and after 4 h for slow release.The sustained release of the Pickering drug carrier prepared with SA as the leading factor remained basically balanced until 24 h,and the sustained release of drug delivery carrier prepared with magadiite as the leading ingredient remained basically balanced after 12 h,while the content of SA is 0 wt%,sustained release of metronidazole keep balance at 10 h.SA can prolong the sustained release time of metronidazole.The correlation coefficients of first order model,Baker-Lonsdale and Korsmeyer-Peppas models are all above 0.9,with high linear correlation.All three models can describe the release kinetics behavior of drug carrier composites.According to the dynamics fitting and the analysis of mechanistic,it was found that SA had a slow release effect on metronidazole due to swelling and dissolving,at the same time,the barrier effect of the lamina reduced the dissolution rate of metronidazole.