Studing On The Formation Process And Mechanism Of Beta-cypermethrin Microemulsion

With lots of virtues, such as high effect and low toxicity, beta-cypermethrinis being used extensively in agriculture, that is made mainly into emulsion.Agro-microemulsion made use of water instead of organic solvent, thatreduced not only endanger of organic solvent to environmental but also cost ofproduce. Now the mainly problem to restrict development ofagro-microemulsion is that stability of that is not good.About the beta-cypermethrin microemulsion, we have studied:1. At first we have screening most of surfactants and co-surfactants, theresults of that indicated, surfactant 150# and 602# being mixed according to theratio 2:3, co-surfactant using hexanol, the stability was best inexperimentations such as the high-temperature preserve, low-temperaturepreserve and normal-temperature preserve.2. With studing some factors' effect to transparence temperature range ofbeta-cypermethin microemulsion, those including the different ratios of ionicand non-ionic surfactant, the kinds of co-surfactant and the contents ofsurfactant, etc. we can make the conclusion that there was an importantrelation between the transparence temperature range of microemulsion and thepolar group of surfactant and co-surfactant molecule. The results indicated thatthe difference of co- surfactants that have only one polar group have littledifference to transparence temperature range of micro-emulsion, that ionicsurfactant compare to non-ionic surfactant has great influence to transparencetemperature range of micro-emulsion.3. Further researching the effects of some factors-including the content ofco-surfactant, the content of surfactant and the maximum addition amount of 3高效氯氰菊酯微乳液形成规律研究和形成机理初探beta-cypermethrin in course of the O/W microemulsion formation, we find thatthere is linear relation between the content of co-surfactant and the maximumaddition amount of beta-cypermethrin, that there is exponential relationbetween the content of surfactant and the maximum addition amount ofbeta-cypermethrin. By a multivatiable linear regression analysis, weestablished the math theory model on the content of co-surfactant, the contentof surfactant and the maximum addition amount of beta-cypermethrin. Y=A+BXc+CExp(DXs) A=2.98,B=1.11,C=1.87,D=0.08634。Y, Xc and Xs represent themaximum addition amount of beta-cypermethrin, the content of co-surfactantand the content of surfactant separately.4. By researching the effects of some factors-such as temperature, content ofsalt, content of co-surfactant , pH value -on the phase diagrams ofpseudo-tricomponent of beta-cypermethrin microemulsion, we analyzed themost best condition about the microemulsion especially O/W microemulsion.The results indicated that high temperature is good to form W/Omicroemulsion, that high content of salt and low pH value are good to formO/W microemulsion, and that the moderate content of co-surfactant is good toform O/W microemulsion.5. Researching further the variety of electric conductivity and interfacialtensions in course of microemulsion formation, and observing directly byelectron microscope, we found the transformation process ofagro-microemulsion, that is with the increase of water content, the phase ofagro-microemulsion changes W/O microemulsion, liquid crystal, bicontinuousand O/W microemulsion sequencely. At the same time, the formationmechanism of agro-microemulsion is discussed.