调酸介质对二甲戊灵微胶囊囊形及粒径的影响

Effect of Adjustable Acid Medium on the Appearance and Particles Size of Pendimethalin Microcapsules

[目的]优选出原位聚合法制备二甲戊灵微胶囊的较佳调酸介质,为二甲戊灵的微胶囊化提供一定的理论指导。[方法]以脲醛树脂为壁材采用原位聚合法制备了二甲戊灵微胶囊,研究了不同调酸介质对二甲戊灵微胶囊囊形及粒径的影响。[结果]5%盐酸溶液作为调酸介质形成的微胶囊囊形粗糙,产生粘连,粒径分布较宽;5%硝酸铵溶液、5%硫酸氢铵溶液作为调酸介质形成的微胶囊囊形松散,容易破裂,产生粘连,粒径分布较窄;5%氯化铵溶液作为调酸介质形的微胶囊囊形光滑致密且坚固,粒径分布较窄。[结论]调酸介质对原位聚合法制备的微胶囊囊形及粒径影响很大,选择合适的调酸介质能获得囊形致密、粒径分布窄的微胶囊。

[Aims] In this paper we optimized the adjustable acid medium for microcapsules of pendimethalin by an in-situ condensation polymerization reaction in order to provide some theoretical guidance for pendimethalin microencapsulation. [Methods] Microcapsules of pendimethalin with a urea-formaldehyde resin wall were prepared by an in-situ condensation polymerization reaction, and the effect of different adjustable acid mediums on the appearance and particles size distribution of the microcapsules were investigated. [Results] When using 5% hydrogen chloride solution as adjustable acid medium, microcapsules could be formed with rough surface and wide-range particle size distribution. When using 5% ammonium nitrate solution or 5% ammonium bisulfate solution as adjustable acid medium, microcapsu[es which were easy to fall into fracture and conglutination could be surface of microcapsules were uncontinuous. When using formed with narrow-range size distribution, meanwhile, the 5% ammonia chloride solution as adjustable acid medium, microcapsules could be obtained with smooth and compact surface, and the particle size of microcapsules were uniform. [Conclusions] Adjustable acid medium was a key point for microeapsules appearance and particles size distribution which were prepared by an in-situ condensation polymerization. High-density and narrow-range particles size distribution microcapsules could be obtained by choosing appropriate adjustable acid medium.