Preparation and Performance Characteristics of Thiamethoxam and Beta-Cypermethrin Compound Pesticide Microcapsule
SONG Si-si;XIA Jiao;WANG Ning;LI Xiao-gang;College of Plant Protection,Hunan Agricultural University,Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China;Hunan Provincial Engineering & Technology Research Center for Bio-pesticide and Formulating Processing;
[Aims] The microcapsule containing thiamethoxam and beta-cypermethrin were prepared with modified poly(propylene carbonate) as carrier. [Methods] The novel biodegradable ploy blends of PPC-PEG was synthesized by solution co-blending with poly(propylene carbonate) and poly(ethylene glycol)(PEG) as raw materials. A series of thiamethoxam and beta-cypermethrin loaded microcapsules with different particle sizes were prepared by solvent evaporation method using PPC-PEG composite material as wall material, thiamethoxam and beta-cypermethrin as core materials and PVA-1788 as disperser. At the same time, the optimal technological conditions for preparation of microcapsules were discussed by orthogonal experiment design. The slow release performances of microcapsules were determined by dialysis bag method. [Results] The encapsulation efficiency and drug loading of blending modified PPC were 53.74, 13.27% for thiamethoxam and 66.02, 32.60% for beta-cypermethrin. The average particle size of microcapsule was 6-8 μm. In addition, thiamethoxam and beta-cypermethrin had the similar release rate. [Conclusions] The microcapsule prepared with PPC-PEG as wall material had a well-defined spherical shape and good sustained release performance, in addition, the concentration ratio of active ingredients close to the optimum compound stoichiometry,which can achieve the purpose of improving the efficacy of the pesticides.