氟乐灵微囊的制备、表征及其光稳定性研究

Preparation and characterization of trifluralin microcapsules and their photo-stability

为增强氟乐灵的光稳定性,提高其有效利用率,以壳聚糖（CS）和甲基丙烯酸甲酯（MMA）为壁材,采用原位聚合法制备了氟乐灵微囊,并测定了其外观形态、粒径及其分布、包封率和载药量,同时研究了其释放特性及其在土壤和水中的光稳定性。结果表明：所制备的氟乐灵微囊呈规则球形;粒径在3~10μm之间,平均粒径为6.5μm;包封率和载药量分别为79%和45%;该微囊具有良好的缓释性能,释放以Fick扩散为主;与氟乐灵乳油相比,氟乐灵微囊的光稳定性显著增强,在试验条件下,其在土壤表面和水中的光解半衰期分别为22 d和173 min。

Trifluralin-loaded microcapsules were prepared by in situ polymerization using chitosan and methyl methacrylate as carder materials in order to enhance its photo-stability and effective utilization. The surface morphology, size and size distribution, encapsulation efficiency and loading content of the resulting microcapsules were determined. The release characteristics and the photo-stability in soil and water of the microcapsules were studied. The trifluralin-loaded microcapsules dispersed as individual particles with a well-defined spherical shape with average size 6. 5 μm. Most of the microcapsules were between 3 and 10 μm. The encapsulation efficiency and loading content of the microcapsules were 79% and 45%, respectively. The trifluralin-loaded microcapsules had a good sustained release performance and the release was controlled mainly by Fick diffusion. Compared with trifluralin emulsifiable concentrate, photo-stability of the microcapsules was enhanced with the half-lives 22 d in soil and 173 min in water under the experimental conditions.