连续有序PP横晶在微纳层状受限空间里的构筑及其性能研究

It has been well established that fabricating the successional and orderly transcrystallization in the confined layered space is one of simple and efficient approaches to achieve the high performance and multi-functional micro- and nano-materials based on polypropylene matrix. We firstly take advantage of the confinement effect of layer-multiplying coextrusion to compel α or β nucleating agent to be selectively distributed in the particular layer. In this multiplied composites, the alternating multilayer composites consist of polypropylene layer and nucleating agent filled-polypropylene layer, and numerous α or β-transcrystallization are generated in this particular confined layer. We aim to gain the tunable structure and morphology of PP- transcrystallization through deeply investigating the crystallization behavior of α or β-transcrystallization in different confined scale gap (micro-scale or nano-scale). Based on the above research, the reinforcement and toughening mechanism of α and β-transcrystallization and will be further probed. Also the behavior of gas barrier and microporous membrane by stretching will be investigated in order to attain the high performance and multi-functional micro- and nano-materials based on PP matrix. The project has been based on the current research and future development trend of PP transcrystallization. The fundamental investigation about the relationship among processing-structure-performance of PP films prepared by layer-multiplying coextrusion will be focused on the basic and key scientific issues. This research will offer a new meaningful idea and method to fabricate continues and orderly PP-transcrystallization, to deepen the fundamental understanding of the behavior of PP-transcrystallization, and to provide the novel theory in terms of high performance and multi-functional micro- and nano-materials based on PP matrix. We truly believe this research will be of great theoretical and practical significance.

在层状受限空间里构筑连续有序横晶是实现PP基微纳材料高性能和功能化的有效途径。本项目首次利用微纳层共挤出的限位效应将α或β成核剂定向分布在PP膜的特定区域，形成PP层和PP/成核剂层交替排列的连续层状结构，在层状受限空间里构筑连续有序的α或β横晶。深入研究α和β横晶在不同尺度层状受限空间（微米级到纳米级）里的结晶行为，实现PP横晶结构和形态的可调控。在此基础上，进一步研究α和β横晶的增强增韧机制，以及α和β横晶的气体阻隔性能和拉伸成孔性，制备高性能和功能化的PP基微纳材料。本申请项目针对PP横晶的研究的现状和发展趋势，围绕基本科学问题开展微纳层共挤出PP膜加工-结构-性能之间相互关系的研究，将为构筑连续有序PP横晶提供新思路和新方法、加深对PP横晶基本性质的理解、为实现PP基微纳材料的高性能和功能化提供新理论，具有重大的理论和现实意义。

聚丙烯（PP）微孔膜附加值高，其产品广泛应用于电池分离膜、人工肺、水净化、化工提纯和服装等领域。随着PP微孔膜应用领域的扩大，开发具有独特性能的新型微孔膜成为一项迫切的任务。P晶体具有丰富的晶型和形态，很大程度上决定PP膜拉伸成孔机理。因此研究具有特殊晶体结构和形态PP膜的拉伸成孔特性对探索该领域基本科学问题和开发新型PP微孔膜具有重要意义。本项目首次利用微层共挤出的限位效应将α或β成核剂定向分布在PP基材的特定区域，形成PP层和PP/成核剂层交替排列的连续层状结构，利用二维层状界面处的高密度成核点诱导连续有序的长方体状PP横晶。深入研究α和β横晶在层状受限空间里的结晶行为，提高PP横晶的结晶度和有序性，实现晶片尺寸和晶片间距离的可调控。在此基础上，进一步研究α和β横晶的力学性能以及拉伸成孔规律和特性，制备孔径可调的新型PP微孔膜。本申请项目针对PP膜结晶和拉伸成孔研究的现状和发展趋势，围绕基本科学问题开展微层共挤出PP膜加工-结构-性能之间相互关系的研究，将为构筑连续有序PP横晶提供新思路和新方法、加深对PP横晶基本性质的理解、丰富PP晶体的拉伸成孔机理，具有重大的理论和现实意义。本项目共发表论文14篇（其中SCI收录12篇），获得国家授权发明专利7项。培养博士毕业生4名，硕士毕业生2名。