| Emulsion polymerization is one of the important methods for production of polyacrylamide. Emulsion polymerization is highly valued by people more and more, because has many advantages in improving the polymerization rate and controlling reaction temperature, and so on. Polymerization process and product performance of Emulsion polymerization cannot be absent of the stability of the emulsion. The stability of the emulsion is one of the difficulties of emulsion polymerization technology.Through adjusting and controlling some factors which influence the emulsion stability and phase behavior, including oil/water ratio, HLB value of emulsifier and the concentration of acrylamide, we studied stability of acrylamide emulsion, looked for the emulsion stability boundary and obtained optimum condition for emulsion stability of acrylamide. The stability of inverse emulsion system containing acrylamide and ferroferric oxide and containing acrylamide and simonkolleite were researched respectively for getting the best recipes.We researched the stability of the emulsion in different HLB value. We found when HLB value was4.3, emulsion stability index increased with increases of oil/water ratio W%. Emulsion stability increased with HLB value from5.0increased to5.74and when HLB value was5.74, emulsion stability index increased Vt got about equal to1. Emulsion stability got worse when HLB value was6.5. We researched emulsion stability boundary and found oil/water ratio W%of border line of W/O and O/W reduced with increases of HLB value no matter what the concentration of acrylamide.We researched the stability of inverse emulsion system containing acrylamide and ferroferric oxide in different oil/water ratio. We found when HLB value was5.7changing from5.1to5.8, Vt got maximum which was between0.85and0.95, and when HLB value was5.1or5.2, Vt got minimum which was between0.5and0.6.We researched the stability of inverse emulsion system containing acrylamide and simonkolleite in different oil/water ratio. We found when oil/water ratio W%was6/4and HLB value was between5.4and5.7, we got the most stable inverse emulsion system; when oil/water ratio W%was6.5/3.5, stability boundary of inverse emulsion system was in the most narrow range; when oil/water ratio W%was7/3and HLB value was between5.4and5.7, we got the most stable inverse emulsion system. Maximum of Vt was0.75and minimum of Vt was0.35in inverse emulsion system containing acrylamide and simonkolleite.Compared with inverse emulsion system between containing acrylamide and ferroferric oxide and containing acrylamide and simonkolleite, we found the stability of inverse emulsion system of the former was better than the latter.We put aqueous phase containing monomers as the internal phase and non-polar oil medium as external phase. Inverse emulsion technology is inverse emulsion polymerization in the water droplets containing monomers and obtained polymer latex particles through emulsification of emulsifier and getting inverse emulsion system by mixing aqueous phase and oil phase. We will get polymer latex particles with different size, shape and structure through adjusting and controlling the proportion of Water phase and oil phase, the kinds and quantity of emulsifier and stirring speed.Taken each water-drop in W/O emulsion system as a mini-reactor and based on the coprecipitation and inverse emulsion polymerization, we obtained Fe3O4/PAM composite nanoparticles. This W/O emulsion system containing Fe3O4/PAM composite nanoparticles was magnetorheological fluid.We found Fe3O4/PAM composite nanoparticles were similar to sphere and the average particle size of composite nanoparticles was311nm. The average particle size of composite nanoparticles had the trend to get smaller with increasing emulsifier blend dosages and had the trend to get larger with increasing Fe3O4contents in polymer latex particles.We found the saturation magnetization value of Fe3O4/PAM composite nanoparticles increased with increasing Fe3O4contents in polymer latex particles in a certain range and exhibited good superparamagnetic properties. The dispersion stability of MR fluids increased with increasing the emulsifier blend dosages and decreased with increasing the Fe3O4contents in polymer latex particles. Under a magnetic field, the MR fluids nearly could not flow and even could be seemed as solid-like materials. The MR fluids showed good rheological properties and their shear stress tended to increase with increasing of shear rate and their shear viscosity tended to decrease sharply with increasing of the shear stress.The simonkolleite is a zinc salt with hexagonal system. One of the important purposes of simonkolleite is preparation of zinc oxide nano porous materials. Reports were very few about preparation methods of nano-simonkolleite. The synthetic methods of reports about nano-simonkolleite had some of the defects including complex preparation step, harsh preparation conditions, and so on. It is very great significance for promoting the process of its application to develop the new method of preparation of nano-simonkolleite under the condition of low temperature and atmospheric pressure.Taken each water-drop in W/O emulsion system as a mini-reactor and based on the precipitation reaction and inverse emulsion polymerization, we obtained Zn5(OH)8Cl2-(H2O)/PAM composite nanoparticles (abbreviation for ZHC/PAM). We found ZHC/PAM composite nanoparticles and simonkolleite crystal were obtained through changing the molar ratio of zinc chloride and acrylamide. The results show that crystal structure of simonkolleite was rhombic hexahedron though XRD test to ZHC/PAM composite nanoparticles and simonkolleite crystal. We found ZHC/PAM composite nanoparticles were similar to sphere and had fluorescent by microscopic examination. Through thermogravimetric analysis to ZHC/PAM composite nanoparticles and simonkolleite crystal, We found zinc oxide was produced by thermal decomposition of simonkolleite.Modified glassy carbon electrode with ZHC/PAM composite nanoparticles by Coating method was researched by Cyclic voltammograms test. We found Modified glassy carbon electrode had good cycle volt-ampere characteristics in mixed solution consisted of potassium iodide and0.5M potassium chloride and formed a quasi reversible cycle volt-ampere curve.We found reduction peak currents and oxidation peak current of cycle volt-ampere curve increased with scan rate changing from20mV s"1to700mV s"1. Reduction of peak voltage moved the negative direction and oxidation peak voltage moved the positive direction and potential difference between reduction peak and oxidation peak increased. The quasi reversible features of cycle volt-ampere curve were clear under the lower scan rate and were transformed seriously under too larger scan rate.We found reduction peak currents and oxidation peak current of cycle volt-ampere curve rapidly increased with potassium iodide concentration increased, peak currents increased exponentially and the quasi reversible degree of cycle volt-ampere curve was enhanced. Using electrode of ZnO/PAM/GCE made check out concentration of potassium iodide reach the parts per million (PPM) level.In addition, using modified electrode of ZnO/PAM/GCE made the electrolyte of FeCl3and CuSO4form irreversible volt-ampere curves which had a larger single peak to FeCl3, had obvious double peaks to CuSO4from-0.1V to-0.9V and did not form obvious peak curve of Oxidation and reduction to methanal.In conclusion, we studied the stability of emulsion system of containing acrylamide, the stability of inverse emulsion system containing acrylamide and ferroferric oxide and containing acrylamide and simonkolleite respectively and got the best recipes. We got Fe3O4/PAM composite nanoparticles and ZHC/PAM composite nanoparticles using inverse emulsion technology and carefully studied their application including magnetorheological fluid and chemical modified electrodes. Theory reference about the stability of inverse emulsion system was provided and the valuable synthetic thinking was provided preparation of composite nanoparticles using inverse emulsion technology through our research works. |
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