Change in the critical nucleation radius and its impact on cell stability during polymeric foaming processes
Change in the critical nucleation radius and its impact on cell stability during polymeric foaming processes
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DOI：
10.1016/j.ces.2009.07.025
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发表时间：
2009-12-01
影响因子：
4.7
通讯作者：
Zong, Jin H.
中科院分区：
文献类型：
--
作者：
Leung, Siu N.;Wong, Anson;Zong, Jin H.
细胞成核的临界半径是由系统温度唯一决定的热力学状态的函数。系统压力，以及聚合物/气体溶液中的溶解气体浓度。由于这些状态变量在发泡过程中是连续变化的，因此临界半径是同步变化的，尽管传统观念认为它是给定初始状态下的固定热力学性质。根据经典成核理论，临界半径决定了气泡的命运。因此，发泡过程中临界半径的变化对泡沫细胞的稳定性有很大的影响，特别是在微孔或纳米孔泡沫的生产中。本研究从理论上论证了在常压下化学发泡剂分解气泡产生和膨胀时临界半径的连续变化。从可视化单元观察到的实验结果用于支持理论推导的概念。通过对气泡尺寸与临界半径的比较，讨论了成核气泡的可持续性。2009爱思唯尔有限公司版权所有。
The critical radius of cell nucleation is a function of the thermodynamic state that is uniquely determined by the system temperature. system pressure, and the dissolved gas concentration in the polymer/gas solution. Because these state variables change continuously during the foaming process, the critical radius varies simultaneously despite the traditional concept that it is a fixed thermodynamic property for a given initial state. According to classical nucleation theory, the critical radius determines the fate of the bubbles. Therefore, the change in the critical radius during foaming has a strong impact on the stability of foamed cells, especially in the production of microcellular or nanocellular foams. In this study, the continuous change in the critical radius is theoretically demonstrated under atmospheric pressure while bubbles are generated and expanded by the decomposition of a chemical blowing agent. The experimental results observed from the visualization cell are used to support the theoretically derived concept. Sustainability of the nucleated bubbles is also discussed by comparing the bubble size to the critical radius. (C) 2009 Elsevier Ltd. All rights reserved.