The Dynamics of Phase Inversion

相转化的动力学

• 批准号: 9421580
• 负责人: Anthony McHugh
• 金额: $ 15万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-03-15 至 1998-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9421580&HistoricalAwards=false
• 关键词: Dynamics; Phase; Inversion

9421580 McHugh, Anthony Phase inversion refers to the process by which a concentrated polymer solution is converted into a solid gel network with desirable, end-use properties. This process plays a central role in a number of polymer material fabrication technologies, the most important of which is membrane formation. The long-range goal of this research iq to advance the fundamental understanding of the generic, dynamic aspects of phase inversion, and, thereby, provide a more quantitative basis for its application in the development of new materials. The proposed work is an experimentally-based study which capitalizes on unique methodologies recently developed in the P.I.'s laboratory for in-situ observation of the diffusion and gelation dynamics which occur when a polymer solution is contacted with a nonsolvent medium. In-situ visualization techniques will be used to monitor the crystallization, macroscopic, homogeneous diffusion, gel growth, interfacial structuring kinetics, and bath-side mass transfer processes which take place in nonsolvent-quenched films. Dynamic small-angle scattering experiments will also be carried out on thermally-quenched solutions to gain new information on the interplay of the various phase separation processes (liquid-liquid phase separation - by spinodal decomposition or nucleation and growth mechanisms, glass transition, and physical gelation) which control the kinetics of formation and morphology of the phase-separated, gel structure. The nonsolvent-quenching experiments will be analyzed in terms of phenomenological models for the diffusion and gelation processes. In the latter case, analysis of the effects of non-equilibrium at the film-bath interface will be carried out to quantify the conditions under which spilodal decomposition, vitrification, and/or nucleation and growth phenomena may be involved in the gelation, and, structure formation processes. Systems to be studied will include amorphous and crystallizable polymers in solvent/nonsolvent co mbinations corresponding to rapid and delayed precipitation quench conditions. Morphological studies of the formed structures will also be carried out using electron microscopy. The experimental and modeling studies of this project will provide important, new information on the structure formation behavior of quenched polymer solutions. It is expected that the results will have a direct carryover in the prediction and control of the processing conditions necessary for the formation of gas separation reverse osmosis and ultrafiltration membranes.

9421580 McHugh，Anthony 相转化是指将浓缩的聚合物溶液转化为具有期望的最终用途性质的固体凝胶网络的过程。 该过程在许多聚合物材料制造技术中起着核心作用，其中最重要的是膜形成。 本研究的长期目标是推进对相转化的一般动态方面的基本理解，从而为其在新材料开发中的应用提供更定量的基础。 拟议的工作是一项基于实验的研究，利用了PI最近开发的独特方法的实验室，用于原位观察当聚合物溶液与非溶剂介质接触时发生的扩散和凝胶化动力学。 原位可视化技术将用于监测结晶，宏观，均匀扩散，凝胶生长，界面结构动力学，和浴侧传质过程中发生的非溶剂淬火膜。 动态小角散射实验也将进行热淬火的解决方案，以获得新的信息的相互作用的各种相分离过程（液-液相分离-通过旋节分解或成核和生长机制，玻璃化转变，和物理凝胶化），控制动力学的形成和形态的相分离，凝胶结构。 非溶剂淬火实验将分析扩散和凝胶化过程的唯象模型。 在后一种情况下，在膜浴界面的非平衡的影响的分析将进行量化的条件下，spilodal分解，玻璃化，和/或成核和生长现象可能涉及的凝胶化，和，结构形成过程。 待研究的系统将包括在溶剂/非溶剂组合中的无定形和可结晶聚合物，其对应于快速和延迟沉淀淬火条件。 还将使用电子显微镜对形成的结构进行形态学研究。 该项目的实验和模拟研究将提供重要的，淬火聚合物溶液的结构形成行为的新信息。 预计这些结果将直接用于预测和控制气体分离、反渗透和超滤膜形成所需的工艺条件。