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Thermodynamic Principles of Precipitation Polymerization and Role of Fractal Nanostructures in the Particle Size Control
Macromolecules ( IF 5.1 ) Pub Date : 2020-07-06 , DOI: 10.1021/acs.macromol.0c00973
Antonio L. Medina-Castillo 1
Affiliation  

The effect of the solvent on the morphology and the particle size of the polymer materials obtained by precipitation polymerization is not yet understood from a physical chemical perspective. Clarifying the effect of the solvent is an important issue to understand the thermodynamic principles of precipitation polymerization and forward the engineering aspects. In this work, we use the scaling theory to deduce the thermodynamic equations that control the phase separation process and particle size in precipitation polymerization at constant T and P. To do so, precipitation polymerization has been undertaken in three steps: (I) coil-to-globule transition, (II) phase separation, and (III) growth stage. The model is then used to analyze the effect of the solvent in precipitation polymerization at constant T and P. To prove the model, we focus on analyzing correlations between the theoretical curves and the experimental curves obtained from precipitation polymerization of a model polymeric system in different solvents and show that we can faithfully reproduce the experimental curves by using the theoretical equations. Finally, we exploit the thermodynamic principles of heterogeneous nucleation on fractal surfaces to develop a novel methodology based on precipitation polymerization in the presence of small concentrations of fractal nanostructures and show how this new approach is able to reduce the particle size up to eight times below the values obtained from conventional precipitation polymerization.

中文翻译:

沉淀聚合的热力学原理及分形纳米结构在粒径控制中的作用

从物理化学的角度,尚不了解溶剂对通过沉淀聚合获得的聚合物材料的形态和粒度的影响。澄清溶剂的作用是理解沉淀聚合的热力学原理并向前推进工程方面的重要问题。在这项工作中,我们使用定标理论推导了热力学方程,该方程控制了在恒定TP下沉淀聚合中的相分离过程和粒径。为此,沉淀聚合已通过三个步骤进行:(I)盘绕至球过渡,(II)相分离和(III)生长阶段。然后使用该模型分析溶剂在常数TP下对沉淀聚合的影响。为了证明该模型,我们着重于分析理论曲线与通过模型聚合体系在不同溶剂中的沉淀聚合获得的实验曲线之间的相关性,并表明我们可以使用理论方程式忠实地再现实验曲线。最后,我们利用分形表面上非均相成核的热力学原理,开发了一种在小浓度分形纳米结构存在的基础上基于沉淀聚合的新方法,并展示了这种新方法如何能够将粒径减小到比分形纳米结构低八倍。由常规沉淀聚合获得的值。
更新日期:2020-07-28
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