复凝聚法制备昆虫激素模拟物十二醇微胶囊及其释放性能

Preparation of Insect Sex Pheromone Simulacrum Dodecanol Containing Microcapsules via Complex Coacervation Method and Its Release Behavior

以明胶(GE)和阿拉伯胶(AG)为壁材,通过复凝聚法将昆虫激素模拟物十二醇(C12OH)包覆在微胶囊中,改变微胶囊壁材的浓度和交联度,探讨了体系中C12OH的可控释放性能.通过对壁材质量比为1及不同pH条件下的壁材凝聚率测试确定最佳复凝聚的pH为4.0;考察了不同分散剂对微胶囊及其分散液性能的影响,确定以Tween20/Span80(质量比1∶1)作为复凝聚法包覆C12OH体系的分散剂.在壁材质量分数大于或等于3%条件下制备的微胶囊粒径大于壁材质量分数为2%的微胶囊,胶囊的载药量和C12OH包覆率明显高于后者.增加交联剂的用量,壁材交联度、胶囊的载药量和C12OH包覆率都显著提高.在相同用量的情况下,用甲醛作交联剂时得到的微胶囊的交联度比用戊二醛作交联剂时的要低,但其对C12OH的包覆率更高.通过扫描电镜对微胶囊进行了分析,认为GE与AG通过复凝聚能够将C12OH包覆在微胶囊内部.对胶囊中C12OH在恒温恒湿条件下的释放研究结果表明,3%与4%壁材含量下1%戊二醛交联的微胶囊和5%壁材含量下4%戊二醛交联的微胶囊中C12OH的释放行为有明显的可控性.通过调节微胶囊的壁材含量和交联度可以达到昆虫激素可控释放的目的.

Dodecanol（ C12OH）, as an insect sex pheromone simulacrum, was encapsulated via complex coacervation with gelatin（GE） and acacia gum（AG） as the wall materials and the release behavior of C12OH from microcapsules was investigated via varying solution concentration and crosslinking of wall materials. Firstly, the yeild of coacervation at different pH was tested when mass ratio of GE to AG was set at 1 ： 1. It was observed that, for the complex coacervation maximum yield was achieved at pH = 4.0. Then properties of microcapsules and dispersions with different dispersants were detected. The results showed that with Tween 20/Span 80 （ mass ratio 1 ： 1 ） as dispersants, it improved the encapsulation efficiency of microcapsules and the stability of the dispersion. When the wall material mass fraction was equal to or higher than 3%, the size of the microcapsules was larger than that prepared with 2% wall material mass fraction and their C12 OH loading and encapsulation rate were remarkably higher than the latter. In addition, increasing of crosslinker led to the capsules with much higher crosslinking, C12 OH loading and encapsulation rates. Microcapsules crosslinked with formaldehyde had a lower crosslinking but a higher C12OH encapsulation rate compared with those crosslinked with glutaraldehyde at equal level. The structure of microcapsules was analyzed through scanning electronic microscopy with the conclusion that it did encapsulate C12 OH in microcapsules. Moreover, to investigate C12OH release from the capsules, microcapsules were placed into an incubator with constant temperature （35 ℃ ） and relative humidity（50% RH）, and taken out for C12OH examination by weighing the samples. It was found that microcapsules prepared with 3% and 4% mass fraction solution of wall materials, crosslinked with 1% glutaraldehyde manifested a controlled C12OH release behavior as well as thoses done with 5% wall materials solution and 1% glutaraldehyde. This work indicates that the release of C12 OH can be well controlled by adjusting polymer concentration and crosslinking of microcapsules. This is of great importance for our ongoing study on the controlled release of authentic insect semiochemicals.