项目名称: 聚丙烯腈浓溶液和凝胶中的相分离研究
项目编号: No.21204096
项目类型: 青年科学基金项目
立项/批准年度: 2013
项目学科: 高分子科学
项目作者: 张若愚
作者单位: 中国科学院宁波材料技术与工程研究所
项目金额: 25万元
中文摘要: 因为内聚能过大,无法熔融加工,聚丙烯腈(PAN)材料一般都从浓溶液或者凝胶态出发,采用析出的方法制备。这种析出的过程实质上就是相分离的过程,相分离过程中的形貌控制是PAN产品控制的核心。在PAN溶液中存在着PAN分子链之间的强极性力作用,以及PAN分子链与溶剂小分子之间的动力学差异。强极性力会导致相分离的动态过程偏离经典的Cahn-Hilliard-Cook理论的描述;而分子间的动力学差异会导致粘弹性相分离的发生,其结果是PAN分相中的形貌不会再是简单的双连续或者液滴悬浮相结构。此外,鲜有对凝胶态中发生的相分离进行的研究。凝胶解体和相分离的同时发生是两个动态过程的耦合。研究这类过程可以充实我们的理论和实验技术,了解其中的形貌变化特点。因此研究PAN分相的动态过程,不仅能够开拓相分离研究的新领域,补充现有的理论和实验现象,而且能对实际生产过程提供有力的指导。
中文关键词: 流变学;相分离;凝胶化;自相似结构;
英文摘要: The Polyacrylonitrile (PLA) chains attract strongly with each other because of the highly polarity group. As a result the melting temperature of PLA is even higher than its thermal degradation temperature. Thus the processing of PLA in industry usually starts from concentrated solution or gel, and then dries the PLA out. Such technique inevitably involves the phase separation of PLA solutions or gels, and actually the control of the phase separated morphology is the key point in industrial processes. However, the strong polarity interaction among the PLA chains and the dynamical asymmetry between the PLA chains and solvent molecules change the phase separation behavior away from the classical theories' descriptions. The polarity interaction will alter the kinetics of phase separation as described by Cahn-Hilliard-Cook theory, and the dynamical asymmetry will induce the viscoelastic phase separation which will change the morphology from the normal bicontinuous or dispersed phase morphology. On the other hand, the phase separation in gel is lack of investigation, while the coupling between gel dissociation and phase separation is of both theoretical and application importance. Thus the investigation of PAN phase separation and the morphological evolution can discover new experimental phenomenon, add up to phase se
英文关键词: Rheology;Phase Separation;Gelation;Self-similar Structure;