Pickering emulsion stabilized by lignin/sodium dodecyl sulfate composite nanoparticles (LSNP) was used as template to prepare the avermectin @ lignin/polyurea composite microcapsules (AVM@LPMC) through ion cross-linking and interfacial polymerization. The inner wall of the microcapsules is a firm and compact polyurea layer, and the outer wall is a loose lignin layer. The effects of stirring speed, dosage of sodium dodecyl sulfate (SDS), and pH value in aqueous phase on the formation of microcapsules were systematically studied. The results showed that the optimal stirring speed was 200 rpm, and the optimal dosage ratio in water phase was HCl (mmol):SDS (mmol):lignin AL (g) = 0.375:1.25:1 in fixed oil-water ratio (1:9) and oil phase composition. In this way, the encapsulation efficiency of microcapsules could reach up to 85.4%, while it would slightly decrease with the increase of lignin content in the wall materials. The polyurea layer played a key role in supporting the spherical structure of the capsule wall and delaying the release of avermectin, while the loose lignin layer contributed less to the slow release performance of microcapsule. By changing the amount of lignin, the polyurea-layer thickness could be regulated to adjust the release rate of microcapsule. Remarkably, a small amount of lignin introduced in the wall material could significantly improve the anti-photolysis performance of avermectin in microcapsules.

中文翻译：

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阿维菌素控释木质素-聚脲复合微胶囊的制备及应用性能

以木质素/十二烷基硫酸钠复合纳米粒子（LSNP）稳定的Pickering乳液为模板，通过离子交联和界面聚合制备阿维菌素@木质素/聚脲复合微胶囊（AVM@LPMC）。微胶囊的内壁是坚固致密的聚脲层，外壁是松散的木质素层。系统研究了搅拌速度、十二烷基硫酸钠(SDS)用量、水相pH值对微胶囊形成的影响。结果表明，最佳搅拌速度为200 rpm，水相中最佳投加量为HCl(mmol):SDS(mmol):木质素AL(g)=0.375:1.25:1，固定油水比(1 :9) 和油相组成。这样，微胶囊的包封率可达85.4%，而随着墙体材料中木质素含量的增加而略有下降。聚脲层在支撑胶囊壁的球形结构和延缓阿维菌素释放方面起关键作用，而松散的木质素层对微胶囊的缓释性能贡献较小。通过改变木质素的用量，可以调节聚脲层的厚度，从而调节微胶囊的释放速率。值得注意的是，在壁材中引入少量木质素可以显着提高微胶囊中阿维菌素的抗光解性能。而松散的木质素层对微胶囊的缓释性能贡献较小。通过改变木质素的用量，可以调节聚脲层的厚度，从而调节微胶囊的释放速率。值得注意的是，在壁材中引入少量木质素可以显着提高微胶囊中阿维菌素的抗光解性能。而松散的木质素层对微胶囊的缓释性能贡献较小。通过改变木质素的用量，可以调节聚脲层的厚度，从而调节微胶囊的释放速率。值得注意的是，在壁材中引入少量木质素可以显着提高微胶囊中阿维菌素的抗光解性能。