Preparation And Performance Study Of Cyhalothrin-thiamethoxam Microcapsule Suspension-suspension Concentrat

Microencapsulation technology has various advantages in pesticide formulation,such as masking the bad smell of pesticides,increasing the chemical stability of pesticides,controlling the release of pesticide molecules and prolonging the validity period.so it became a key means to improve pesticide utilization efficiency,decrease pesticide consumption,and solve pesticide pollution problem.However,due to the poor quick effect of microcapsules at the initial stage of release,it is not conducive to the prevention and control of sudden diseases and pests,the novel multifunctional ZC makes up for the deficiency of microcapsule formulations,expands the application scope of the formulations,makes the novel multifunctional ZC has both quick effect and sustained effect,and enables the formulations to protect plants from pests and diseases.1.Lambda-cyhalothrin has low toxicity to the environment and high biological efficiency,and has a high insecticidal spectrum.The traditional beta cypermethrin processing dosage form has the disadvantages of strong odor,poor stability and strong irritation to human skin and eyes,It is degraded quickly by the enviromental impact,and the persistent insecticidal efficacy is short.In this thesis,taking wall material,emulsifier,solvent,dispersant,initiator and other factors as variables.The types and dosages of solvent,emulsifier,capsule material,dispersant and initiator were screened respectively based on the appearance and morphology,particle size distribution,microcapsule encapsulation state and encapsulation rate,and the type and dosage of Lambda-cyhalothrin were determined.Using the response surface method,taking the water bath temperature,water bath time and stirring rate as the response variables,and taking the Lambda-cyhalothrin microcapsule D90 as the response value,the effects of various factors and levels on the particle size D90 of Lambda-cyhalothrin microcapsule were discussed,and finally the best preparation process parameters for the preparation of Lambda-cyhalothrin microcapsule were determined.The microcapsules were characterized in detail by optical microscope,scanning electron microscope,laser particle size distribution analyzer,Fourier transform infrared spectroscopy analysis,thermal stability analysis and other methods.The optimal process of Lambda-cyhalothrin microcapsule obtained by response surface experiment is as follows: stirring rate of 300r/min,water bath temperature of 50 ℃ and water bath time of 3 h.The prepared Lambda-cyhalothrin microcapsules have good appearance,good thermal stability and uniform particle size distribution,the D50 of Lambda-cyhalothrin microcapsules is 2.034μm,and the EE% is 91.91%;The release model was established and fitted with the release model.The fitting results showed that the release of the prepared microcapsules under different conditions accorded with the first-order release model.Through the fitting with the model,it was judged that the diffusion mechanism of Lambda-cyhalothrin in microcapsules was the main mechanism.The above research results show that the Lambda-cyhalothrin microcapsules prepared by the interfacial polymerization method have good appearance and high coating rate,the preparation process is easy to operate,and the microcapsules have good sustained-release performance,which provides a certain reference value for the majority of researchers.2.In this thesis,the novel multifunctional ZC was prepared by mixed Lambda-cyhalothrin microcapsule and thiamethoxam suspension,aiming at the traditional microcapsule suspension the problem of poor quick effect in the initial stage of release,which is not conducive to the prevention and control of sudden diseases and pests.In this thesis,In order to ensure the physical and chemical stability of the system,the effect of p H structure adjustment agent and the stability of ZC at different temperatures,the ZC of detection and evaluation.The bioactivity experiment of peach aphid showed that compared with a control preparation,the prepared ZC has both quick effect and sustained effect on biological control,which provided a reference for the development of new multifunctional microcapsule formulation.