高分子绝缘导热复合材料交替层状导热网络的构筑及其特性研究

In order to construct the thermoconductive network with high efficiency in polymer thermoconductive & electrically insulating composites, the alternating multilayered composites with thermoconductive & electrically insulating layers and thermoconductive & electrically conductive layers were prepared through layer-multiplying extrusion. As continuous layered structure, thermoconductive & electrically conductive layers have the benefits of the electronic thermal conductivity in the plane of the layer. The thermoconductive network perpendicular to the plane of the layer can be improved through the addition of different kinds of the thermoconductive fillers with different morphology and size, as well as the adjustment of the layer number and the layer thickness ratio. Morphology development of different kinds of the thermoconductive fillers in two-dimensional confined space and its effects on the properties of the composites will be investigated. The formation and thermoconductive mechanism of three-dimensional alternating multilayered thermoconductive network will be proposed. The project is based on the current research of polymer thermoconductive & electrically insulating composites and their future development trend. The fundamental investigation about the relationship among processing, structure and performance of the composites will be focused on the basic and key scientific issues. The research will offer a novel idea and method to construct the thermoconductive network with high efficiency, to deepen the fundamental understanding of special performance of three-dimensional alternating multilayered thermoconductive network, and to richen the thermoconductive & electrically insulating mechanism, as a result, high performance sheets/films based on polymer thermoconductive & electrically insulating composites can be prepared successfully. We truly believe that the research will be of great theoretical and practical significance.

本项目首次利用微层共挤出技术将高分子绝缘导热复合材料设计为绝缘导热层和导电导热层交替排列的层状复合结构来构筑高效导热网络。导电导热层作为单层连续结构能在单层平面内发挥高效的电子导热网络的优势，通过引入不同种类、形态和尺度的导热填料进行杂化复配并调控层数和层厚比以构筑垂直于层状片材或膜的高效导热网络。研究不同导热填料在二维层状受限空间里的形态演变规律及其对复合材料宏观性能的影响，阐明三维交替层状导热网络的形成和导热机理。本申请项目针对高分子绝缘导热复合材料研究的现状和发展趋势，围绕基本科学问题开展具有三维交替层状导热网络的高分子绝缘导热复合材料加工成型-微观形态结构-宏观性能之间相互关系的研究，将为构筑高效的绝缘导热网络提供新思路和新方法、加深对交替层状导热网络特性的理解、丰富绝缘导热机理，最终制备得到高性能的高分子绝缘导热复合片材或膜，具有重大的理论和现实意义。

如何高效调控导热填料的多层次形态结构并利用本征导热性能更高的导电导热填料构筑绝缘导热通路是实现高分子基绝缘导热复合材料高性能化和多功能的重要途径。本项目通过加工方法的创新，利用微纳层叠过程及其多级双向拉伸剪切复合力场构建了导电导热填料和绝缘导热填料在高分子熔体中的均匀分散、高度取向、二维交替层状分布和三维密实绝缘导热通路，建立了高性能多功能绝缘导热复合材料规模化制备的新方法、新技术。本项目围绕高分子基绝缘导热复合材料加工-结构-形态-性能之间的关系开展工作，取得了如下成果：（1）构筑功能填料的均匀有序结构实现了导电导热填料在绝缘导热复合材料中的高效利用；（2）构筑不同功能填料的交替层状分布实现了高效绝缘导热和抗静电等多功能；（3）利用层间压迫作用构筑以导电导热填料为主且具有高取向、交替层状排布结构的三维密实杂化绝缘导热粒子网络显著增强了绝缘导热性能；（4）引入少量本体纤维构筑长程有序的增强隔离结构导热网路实现了绝缘导热和力学性能的同步增强。本项目阐明了绝缘导热复合材料微观形态结构与宏观性能的对应关系，揭示了导热网络的形态演变规律和形态调控机理，提出了高效绝缘导热通路的形成和导热机理，发展了高分子复合材料形态调控的新技术。