Preparation Of Magnetic Nanoemulsion By Pickering Emulsion Polymerizatio

In this paper,the stability mechanism Fe3O4 in aqueous phase were discussed in depth by analyzing the relationship between stability and Zeta potential of these nanoparticles.a waterbased magnetic fluid without obvious aggregation was obtained by modifying the surface of Fe3O4 nanoparticles.Then,the Pickering emulsion polymerization experiments were carried out with Fe3O4 and modified Fe3O4 nanoparticles as stabilizers respectively.The instability phenomenon and polymerization kinetics during Pickering emulsion polymerization were investigated in detail.Finally,a stable Pickering emulsion was successfully prepared.The content of the paper is mainly composed of the following three parts:1.The co-precipitation method was used to synthesize Fe3O4 nanoparticles in the aqueous phase.The stability of magnetic nanoparticles in water phase with time were studied in detail after the nanoparticles were treated with different pH conditions,different stirring rates and different ultrasonic time.It was found that pH had the greatest influence on the stability of the Fe3O4 nanoparticles.When the pH was 4,the two nanoparticles have better stability in the aqueous phase.Stirring and ultrasound can only slightly extend the time for nanoparticles to settle,but have little effect on the final stability of nanoparticles.The magnitude of Zeta potential can directly reflect the stability of magnetic nanoparticles in the aqueous phase by comparing the effects of different pH conditions,different stirring rates and different ultrasonic times on the Zeta potential and stability of nanoparticles.The aggregation dynamics of magnetic Fe3O4 nanoparticles can be described by the measured Dh.The tendency of the nanoparticles to increase in size with time can reflect the aggregation behavior of the particles in the aqueous phase.2.Glycine,L-glutamic acid,citric acid,trisodium citrate,and these four small molecules containing carboxylic acid groups or carboxylates were used as modifiers of Fe3O4 nanoparticles.The stability,isoelectric point,aggregation dynamics of the modified Fe3O4 nanoparticles in the aqueous phase were discussed with Zeta potential and particle size as dependent variables,different pH,different stirring rate,different ultrasonic time,and different ionic strength as independent variables.These results showed that when the pH condition is acidic,the Fe3O4 nanoparticles modified with glycine and L-glutamic acid have better stability.Stirring and ultrasound have little effect on the aggregation rate of nanoparticles.These Fe3O4 nanoparticles modified by citric acid and trisodium citrate have better stability under neutral or alkaline conditions(pH greater than 6).3.Fe3O4,and modified Fe3O4 magnetic nanoparticles were used as stabilizers in the Pickering emulsion polymerization process.These results showed that the magnetic nanoparticles in the citric acid-modified Fe3O4 could act as stabilizers in Pickering emulsion polymerization.The effects of the pH of magnetic nanoparticle suspension,the content of magnetic nanoparticles,hydrophilic monomers and hydrophobic monomers on the polymerization results and polymerization kinetics were discussed in detail.Using GayChapman-Stern electric double layer theory to explain the positive and negative changes of the Zeta potential on the surface of latex particles,it was confirmed by scanning electron microscope(SEM)that magnetic nanoparticles were adsorbed on the surface of polymer particles,and the incorporation efficiency(IE)of magnetic nanoparticles to polymer particles was evaluated by thermogravimetric analysis(TGA).P.John Feeney’s equation was used to describe the effect of the ionic strength of ammonium sulfate on the number density of latex particles.Finally,the Pickering emulsion polymerization mechanism was proposed by analyzing the experimental data of the polymerization kinetic curve.