Preparation And Sustained-release Behavior Research Of Chlorpyrifos·beta-cypermethrin Microcapsule Suspension

The current domestic research on the distribution of pesticide has drawn increasing public attention,and it also has a lot of research on microcapsules distribution.For chlorpyrifos and beta-cypermethrin distribution of microcapsules formulations have been studied,the main formulation is EC,which consumed a lot of organic solvent,and resulted in environment pollution and effective time is short,but microcapsules can avoid forenamed problems.So we have studied chlorpyrifos and beta-cypermethrin microcapsules with UF-resin and MF-resin via in-situ polymerization,obtained the optimal conditions of formulation and technics,and main contents is as the following aspects:1.For the screening the formulation of solvent,emulsifier,dispersant,thickener and UF prepolymer dosage of chlorpyrifos and beta-cypermethrin microcapsules,and the optimal conditions were as follows:solvent was dimethylbenzene,emulsifier was 700#,dispersant was KY555,the dosage of dimethylbenzene,700#,KY555 were 7.5%,3.0%,2.5%,respectively,added 15%of UF prepolymer and 0.2%of thickener.2.Using MF-resin as capsule wall to prepare microcapsules in reasonable formula.The influences of adjustable speed of pH,stirring speed,curing phase of heating,curing temperature and curing time on microcapsules were studied under the condition of fixed single factor.Then,obtained the optimal conditions of technics as follows:Using hydrochloric acid concentration of 5%to dispatch system to pH 2.5 in the speed of 0.2g/30min within 2.0 h,controlled the stirring speed of 1200 r/min,curing phase within 30 min to heat up to 55 ?,and then curing 2.0 h.3.According to the release mechanism of microcapsules,the release behavior of optimized microcapsules was studied in comparing with its TC,different conditions of water and soil,and discovered it had good slow release effect.The investigation of microcapsules release behavior in the soil showed that the release kinetics in early 12 days was conformed to one level release equation,the release kinetics of 12 days to last was followed with zero level release equation.