木质素─聚乙二醇交联聚合物微胶囊的制备及其包埋缓释调控机制

The pesticide microcapsules have the advantages such as lasting effect, less toxicity and environment friendly properties, regarded as the trend of the future new formulation of pesticide. However, the technology of the wall materials of microcapsule is undeveloped, which have the flaws such as refractory to degradation, easily broken capsule and phytotoxicity, low cost performance. Nowadays, the undeveloped technology of the wall materials becomes the bottleneck of the pesticide microcapsule technique. In this project, the grafting, crosslinking and polymerization are innovatively used to synthesize a green degradable lignin-based cage type composite wall material, which are used to prepare avermectin microcapsules. The process and mechanism of the grafting and polymerization between Alkali Lignin (AL) and polyethylene glycol (PEG) are studied to disclose the adjusting methods of the molecular weight, size distribution and steric configuration of the obtained lignin-PEG wall materials. The solution behavior and physical and chemical properties of lignin-PEG wall materials in different polar mediums are studied to disclose the laws of cage mouth opening and cage mouth closing in different polar mediums, and obtain the related adjusting methods. The avermectin is loaded in the lignin-PEG wall materials, and the loading process and phase separation method are optimized. Base on the studies, the loading and releasing models of active compounds in lignin-PEG wall materials are established. The research findings present the technical reference and theoretical direction for the investigation and application of lignin-based macromolecular wall materials of microcapsules.

微胶囊农药具有药效持久、毒性低、环境友好等优点，是未来农药新剂型的发展趋势。但是目前微胶囊壁材技术不成熟，存在难降解、容易破囊而致药害、性价比差等缺陷，成为制约我国农药微胶囊剂技术的瓶颈。本项目通过接枝、交联、聚合反应创新性地合成一种绿色可降解的木质素基笼形微胶囊复合壁材，用于阿维菌素微胶囊的制备。通过研究碱木质素与PEG的接枝聚合反应工艺和机理，揭示碱木质素-PEG交联聚合物的分子量、粒径分布和空间构型的调控方法，实现对木质素-PEG壁材的结构调控。通过研究木质素-PEG壁材在不同极性介质中的溶液行为和物化特性，揭示木质素-PEG壁材在水和极性介质中的笼口张开和笼口闭合规律及其调控方法，优化木质素-PEG微胶囊壁材对阿维菌素原药的包埋工艺和相分离方法，建立木质素-PEG微胶囊壁材对原药的包埋和缓释模型。研究结果为木质素基高分子微胶囊壁材材料的研究和工业应用提供技术借鉴和理论指导。

阿维菌素是一种超高效、广谱、无公害的第三代生物农药，广泛用于农业害虫的防治。阿维菌素分子中含有共轭双键和大环内酯结构，在其使用过程中紫外线的照射、气温和土壤环境都会促使其分解，严重限制了其使用和药效发挥。为了解决阿维菌素的光解和药效持久的问题，将微胶囊技术引入到阿维菌素制剂中。.本项目以木质素磺酸钠和碱木质素为原材料，通过化学改性分别制得四种不同结构的木质素基微胶囊壁材和微球载药材料，如下：.1.制备碱木质素聚氧乙烯醚，可与聚乙烯亚胺进行静电自组装成囊，再用戊二醛交联固化得到具有良好性能的阿维菌素微胶囊。.2.揭示木质素磺酸钠在浓溶液中的聚集行为及微结构的变化规律。通过静电及疏水自组装的方法，首次在木质素磺酸钠浓溶液体系中制备出粒径可控的木质素疏水纳米微球。以其为载药材料制备的木质素基载药微球除了具有缓释功能外，还具有抗光解功能，经50小时紫外光照后阿维菌素的保留率高达90.39%，半衰期延长到阿维菌素原药的7.35倍。.3.以碱木质素为原材料，采用烷基酰化改性的方法制备乙酰化碱木质素和苯甲酰化碱木质素，并以此材料制备木质素基载药微球。经50小时的紫外光照后阿维菌素的保留率分别为67.61%和77.01%。.4.以木质素磺酸钠为原材料制备具有pH响应性的木质素聚合物，利用其pH响应聚集特性包裹阿维菌素，采用戊二醛进行交联制备性能优异的微胶囊。制备的微胶囊具有较高的包封率（90%），并且具有良好的稳定性能（避光保存30天性能无明显下降）和优秀的抗光解性能（紫外光照50 h后阿维菌素保留率约为90%）。.本项目制备的系列不同结构的木质素基材料是一种天然、绿色可再生的新型功能材料，可广泛应用于农药的控制释放制剂中。本项目拓宽了农药微胶囊和微球的载药材料，并提出了新的微胶囊和微球的合成工艺。本项目可为木质素基微胶囊壁材和微球载药材料的研究和工业应用提供技术借鉴和理论指导。