Ricardo Fabián, Pradilla Diego, Luiz Ricardo, Alvarez Solano Oscar Alberto
Grupo de Diseño de Productos y Procesos (GDPP), Department of Chemical and Food Engineering, Universidad de los Andes, Bogotá 111711, Colombia.
The Dow Chemical Company, Dow Brasil Sudeste Industrial Ltda, Sao Paulo 04794-000, Brazil.
Polymers (Basel). 2021 Feb 22;13(4):644. doi: 10.3390/polym13040644.
This work applies a multi-scale approach to the microencapsulation by interfacial polymerization. Such microencapsulation is used to produce fertilizers, pesticides and drugs. In this study, variations at three different scales (molecular, microscopic and macroscopic) of product design (i.e., product variables, process variables and properties) are considered simultaneously. We quantify the effect of the formulation, composition and pH change on the microcapsules' properties. Additionally, the method of measuring the strength of the microcapsules by crushing a sample of microcapsules' suspension was tested. Results show that the xylene release rate in the microcapsules decreases when the amine functionality is greater due to a stronger crosslinking. Such degree of crosslinking increases the compression force over the microcapsules and improves their appearance. When high levels of amine concentration are used, the initial pH values in the reaction are also high which leads to agglomeration. This study provides a possible explanation to the aggregation based on the kinetic and thermodynamic controls in reactions and shows that the pH measurements account for the polyurea reaction and carbamate formation, which is a reason why this is not a suitable method to study kinetics of polymerization. Finally, the method used to measure the compressive strength of the microcapsules detected differences in formulations and composition with low sensibility.
这项工作将多尺度方法应用于界面聚合法微胶囊化。这种微胶囊化用于生产肥料、农药和药物。在本研究中，同时考虑了产品设计（即产品变量、工艺变量和性能）在三个不同尺度（分子、微观和宏观）上的变化。我们量化了配方、组成和pH值变化对微胶囊性能的影响。此外，还测试了通过挤压微胶囊悬浮液样品来测量微胶囊强度的方法。结果表明，由于交联更强，当胺官能度更大时，微胶囊中的二甲苯释放速率降低。这种交联程度增加了微胶囊上的压缩力并改善了它们的外观。当使用高浓度的胺时，反应中的初始pH值也很高，这会导致团聚。本研究基于反应中的动力学和热力学控制对团聚现象提供了一种可能的解释，并表明pH测量说明了聚脲反应和氨基甲酸酯的形成，这就是为什么这不是研究聚合动力学的合适方法的一个原因。最后，用于测量微胶囊抗压强度的方法对配方和组成差异的检测灵敏度较低。
