脲醛树脂胶粘剂制备毒死蜱微胶囊

采用工业生产的脲醛树脂胶粘剂为原料，通过原 位聚合法制备了毒死蜱微胶囊，探讨了影响微胶囊性能的主要因素。结果表明，固化剂种类 、壳芯比和反应温度对载药量和包封率的影响较为显著，反应时间和加酸速度对载药量和包 封率的影响不大。在乙酸、草酸、对甲苯磺酸3种固化剂中，草酸效果最好；随着壳芯比的 提高，收率和包封率提高，载药量略有降低；随着反应温度升高，包封率和收率明显降低， 而载药量的变化不大。反应温度较低、加酸速度较慢的微胶囊表面较平滑。经过优化后的制 备工艺为：固化剂为草酸，壳芯比为0.94，反应温度为40℃。在此条件下制得的微胶囊 ，其载药量可达67.66%，包封率为87.68%，收率为88.23%。用本方法在较低的反应温度 下制备的微胶囊的性能不低于同等条件下以尿素和甲醛为原料制备的微胶囊，表明本法是一种简便而效果较好的毒死蜱微胶囊制备方法。

Encapsulation of chlorpyrifos in microcapsules prepared using industrial urea-formaldehyde adhesive

Poly(urea formaldehyde) (PUF) microcapsules loaded with chlorpyrifos were prepa red by in situ polymerization using an industrial urea formaldehyde adhesive. T he main factors affecting the properties of the microcapsules were investigated, and the conditions for preparing the microcapsules were optimized. The results showed that the variety of the curing agent, the shell/core ratio and the reacti on temperature all significantly affect the drug loading, the encapsulation effi ciency and the release rate of the microcapsules, and that the reaction time and the speed of addition of the acid also have a slight effect on the properties o f the microcapsules. The optimized reaction conditions were found to be: oxalic acid as curing agent; shell/core ratio of 0.94; reaction temperature of 40 °C. The microcapsules prepared under these conditions had a 67.7% drug loading, 87.7% encapsulation efficiency and 88.2% yield. Microcapsules prepared in this w ay had comparable properties to those prepared under equivalent conditions by in situ polymerization of urea and formaldehyde.