Abstract

Different technologies to prepare long term pesticide forms include polymer coating, preparing composites and encapsulating pesticides in nanoparticles. A simple and low-cost method was proposed to obtain slow-release formulations by co-extrusion of a pesticide with a biodegradable polymer at a temperature above the melting points of both components. A herbicide metribuzin and low-melting polyester poly-ε-caprolactone were chosen for this work. Formulations containing 10%, 20%, and 40% herbicide were prepared. During 7 days of their exposition in water, it was released from 81% to 96% of initially loaded metribuzin; the highest release was detected for 40%-loaded forms. Biodegradation of the constructs and pesticide release were further studied in the model soil. Degradation rates of the specimens increased with an increase in pesticide content, from 9% to 20% over 14 weeks for the 10%/20%-loaded and the 40%-loaded specimens, respectively. The release of metribuzin reached, respectively, 37–38% and 55%. The herbicide content in soil was lower due to its partial degradation in soil; it reached 23–25% and 33%, respectively, from initially loaded into the polymer matrix. Release kinetics of metribuzin in water as in soil best fitted the First-order model. The used approach is promising for obtaining long-term release formulations for soil applications.

摘要

制备长期农药形式的不同技术包括聚合物涂层、制备复合材料和将农药封装在纳米颗粒中。提出了一种简单且低成本的方法，通过在高于两种组分熔点的温度下将农药与可生物降解聚合物共挤出来获得缓释制剂。这项工作选择了除草剂 metribuzin 和低熔点聚酯聚-ε-己内酯。制备含有 10%、20% 和 40% 除草剂的制剂。在它们在水中暴露的 7 天期间，它从最初加载的 metribuzin 的 81% 释放到 96%；对于 40% 加载的表单，检测到的释放量最高。在模型土壤中进一步研究了构建体的生物降解和农药释放。样品的降解率随着农药含量的增加而增加，对于 10%/20% 加载和 40% 加载的样本，在 14 周内分别从 9% 到 20%。赛克津的释放量分别达到了 37-38% 和 55%。由于在土壤中部分降解，土壤中的除草剂含量较低；从最初加载到聚合物基质中，它分别达到了 23-25% 和 33%。赛克津在水中和土壤中的释放动力学最符合一阶模型。所使用的方法有望获得用于土壤应用的长期释放配方。赛克津在水中和土壤中的释放动力学最符合一阶模型。所使用的方法有望获得用于土壤应用的长期释放配方。赛克津在水中和土壤中的释放动力学最符合一阶模型。所使用的方法有望获得用于土壤应用的长期释放配方。