以密胺树脂为壁材的甲基嘧啶磷微胶囊的制备与表征

Fabrication and characterization of pirimiphos-methyl microcapsules with melamine resin as wall materials

为提高甲基嘧啶磷的稳定性,采用原位聚合法成功制备出以密胺树脂为壁材的甲基嘧啶磷微胶囊,主要探究p H值和芯壁比对微胶囊性能的影响,并通过傅里叶红外光谱仪、扫描电子显微镜、激光粒度分析仪、高效液相色谱等方法对微胶囊的粒径、形貌、载药量、包封率、热稳定性以及缓释性能进行分析.实验结果表明:当反应体系的p H值为5时,生成的微胶囊具有规则的球状结构、良好的热稳定性以及最高的包封率;当微胶囊的芯壁比低于15∶16时,农药微胶囊的热贮存损失低于5%;此外,微胶囊中活性物质的缓释速率可以通过调节芯壁比得到有效控制.

In order to improve the stability of pirimiphos-methyl(PM),PM microcapsules with melamine resin as wall material were fabricated successfully by in-situ polymerization.The effects of pH value and core/wall ratio on the properties of the microcapsules were investigated.The particle size,morphology,pesticide loading,encapsulation efficiency,thermal stability and sustained release property of the microcapsules were analyzed by Fourier transform infrared(FTIR)spectroscopy,scanning electron microscopy(SEM),laser particle size analysis(LPSA)and high performance liquid chromatography(HPLC).The results showed that the prepared microcapsules had regular globular structure,excellent thermal stability and high encapsulation efficiency when pH value of the reaction system was 5.The thermal storage loss of the microcapsules was less than 5%when the core wall ratio was lower than 15∶6.In addition,the slow-release rate of the active ingredients in microcapsules can be effectively controlled by adjusting the core/wall ratio.