Studing On The Properties And Mechanism Of The Formation Process Of Atolachlor Emulsion In Water

Following the development of the pesticide production,the pressure of circumstance protection caused by pesticides is getting worse and worse. The pesticide agent producing is an effective approach to postpone this pressure, it is facing both a big opportunity and a great challenge. Agro-oil-in- water emulsions developped quickly in the last few years because it can fit the need of water solution pesticide agent producing. However, the current research is mainly focused on simple formula screenning on the home and abroad. This thesis chose acetochlor as the research objects. On the base of the research we have done before, we did more research about the influence factors of agro- oil-in-water emulsions forming mechanisms. The following aspects were studied in this thesis :1. We have screened out the emulsifers, cryoprotectan and suspending agent by measuring the particle size and stability of different formulations of acetochlor emulsion in water, then the best formula of acetochlor emulsion in water was ascertained as follows: NR600: 6% Propanetriol as the cryoprotectan: 5% Acetochlor: 40% The rest was water.2. The rheological characteristics of atolachlor emulsion in water was measured. The results showed that its fluid form behaves as plastic fluid and its viscosity was lowered in extent with temperature raises.3. Formation of emulsions has been studied in the system water/polyoxyethylene styrenyl phenyl ether(NR600)/acetochlor by four emulsification methods: (P1)stepwise addition of water to a oil-surfactant mixture, (P2)stepwise addition of a water-surfactant mixture to oil, (D1)stepwise addition of oil to a solution of surfactant in oil, (D2)stepwise addition of a oil-surfactant mixture to water. Their particle size was determined by laser particle sizer, and their stability mechanisms were derived from determining their rheological characteristics and verified by the microphotographs. The results indicate that the emulsions that produced by different emulsification methods have different particle size distributions and their particle size is P1D2>P1>D1, D1 and D2 can't keep stability at high temperature. The four kinds of emulsions behave different rheological characteristics, the values of their viscosity in comparison are: P2>D2>P1>D1, P2 and D2 have the shear-thinning behaviors. Emulsions prepared by different emulsification routs have different microstructures: P1 and D1 are simple emulsions, P2 and D2 are multiple emulsions.4. We initially explored the effects about the structure of surfactants on the particle size and stability of acetochlor emulsion by studying the properties of emulsions prepared by different NR600#.The results show that stable acetochlor emulsions have the nearly the same particle size, their surface tension in comparison are: NR601#< NR602#< NR603#.5. The particle size, microstructure and rheological characteristics of acetochlor emulsions prepared by P1 and P2 were further studied by particle determination, conductivity and viscosity methods.The results show that the viscosity for the system prepared by phase inversion methods both passed a maximum value with the content of water varied, and the moment of which the droplets were closed-packed in microstructure.