纳米网状结构PA6/PEG定形相变材料的原位浇铸制备及其结构性能研究

The method of controlling the microstructure of nanomaterials is critical to obtain form-stable phase change materials (FSPCM) with high performance, in which nanomaterials act as supporting substances. Recently, we find that PA6 nanofibers could be in situ formed during in situ fiber-forming casting, and the PA6/PEG FSPCM with nanonet-like PA6 which acts as the supporting one has high latent heat and good reliability. Based on our previous studies, the influence of the molecular structure of blocked PEG on the morphology of PA6 and the process about in situ fiber-forming of PA6 will be explored, and then the mechanism of the in situ formation of PA6 nanofibers will be induced. Meanwhile, the principle of the form-stable property during phase change and the relationship between reactive system, microstructure and macro-properties will be investigated, based on the exploration of the hydrogen bonding interaction and capillary force between PA6 nanofibers and the blocked PEG and the research of the influence of nanonet-like PA6 fibers on the properties of PA6/PEG FSPCM. This project aims to develop a novel method to prepare a kind of FSPCM with polymer nanofibers acting as supporting substances, and to promote the development of new technology and theory and the application with high performance of FSPCM, which has a very important scientific and practical significance.

通过制备新方法调控纳米材料微观形态结构，是实现以纳米材料为支撑的定形相变材料高性能化的重要途径。申请人近期研究发现：采用原位反应成纤浇铸法，可使PA6原位反应成纤，并制备获得纳米网状结构PA6为支撑的潜热高、可靠性好的新型PA6/PEG定形相变材料。为了探明其机理，本项目拟在前期工作基础上，通过研究封端PEG分子结构对PA6微相结构的影响机制，以及PA6原位反应成纤过程，探究PA6的原位纳纤化网状化机理；研究纳纤PA6与PEG之间的氢键作用和毛细管力等两相界面作用机制，以及纳米网状结构PA6纤维对PA6/PEG定形相变材料性能的影响，探究新型PA6/PEG定形相变材料的定形相变机理，以及反应体系-微观结构-宏观性能之间的相互关系。项目成果旨在开拓一种以聚合物纳纤为支撑的高性能定形相变材料制备新方法，促进定形相变材料制备新技术与理论的发展及其高性能化应用，因而具有重要的科学与现实意义。

采用原位反应成纤浇铸法，可使PA6原位反应成纤，并制备获得纳米网状结构PA6为支撑的潜热高、可靠性好的新型PA6/PEG定形相变材料（FSPCM）。通过测试分析发现，PA6在体系中以纳米纤维状或网状形式存在；所制备的FSPCM的最大潜热为95J/g，相变温度在40~60℃，在热循环100次后，样品的热性能没有明显变化，且样品在100℃下具有良好的热稳定性；该方法制备的FSPCM适用于热能存储。为了探究PA6的纳纤化机理，采用不同分子量PEG和不同PA6含量，制备FSPCM。通过对形貌结构进行研究，可知PA6在体系中的形貌与PEG分子量和含量有关，这主要是由于CL与封端剂的氢键作用导致的。此外，为了研究材料的定形相变机理，采用络合纺丝法制备了PEG/BN/CNF/CS纤维，发现CNF与PEG和BN-OH之间存在氢键作用，材料具有定形相变特性。这说明氢键作用对于防止相变材料的泄露具有至关重要的作用。