石墨烯/碳纳米管复合纤维结构设计与高导热特性研究

Fiber material with excellent mechanical and thermal conducting properties is one of the key materials for developing advanced structural composites with high thermal conductivity. It has long been a hot topic to assemble super-strong, highly thermal conducting nano-carbon materials like carbon nantoubes and graphene into macrostructures, and make fully usage of the superb properties of these nanomaterials in the macroscale. In this study, graphene oxides are introduced into the continuous carbon nanotube networks made using the floating catalyst chemical vapor deposition method, and are then carbonized and graphitized to form the final hybrid nanocarbon fibers. We will systematically investigate the effect of the synthesis parameters on the structures of individual CNTs and their networks, the effect of graphene oxide size on the their distribution in the CNT networks, the structural evolution of the graphene/CNT hybrid fiber during the carbonization and graphitization process, as well as the links between the microstructure of the graphene/CNT hybrid fibers and their mechanical, electrical, and thermal properties. The relationship between the fiber processing, microstructures, and mechanical/thermal properties of these hybrid fibers will then be summarized, which would provide helpful guidance for their future application.

兼具高力学性能、高热导率的纤维材料是高导热结构复合材料的关键基础材料之一。将具有优异力、热性能的碳纳米管和石墨烯等进行可控宏观组装、并在宏观组装体中充分发挥纳米碳材料的优异性能是近年来人们一直关注的热点。本项目拟将氧化石墨烯与浮动催化化学气象沉积法制备的碳纳米管网络进行复合，并通过炭化和石墨化后处理，设计和制备高导热纳米碳纤维材料。系统研究生长条件对碳纳米管自身和网络结构的影响，探索氧化石墨烯结构对其在碳纳米管网络中分布的影响规律，揭示在炭化及高温石墨化过程中石墨烯/碳纳米管复合纤维的微观结构演变过程，并阐明其对复合纤维力学和热学性能的影响机制，建立复合纤维制备工艺-微纳结构-力热性能关系，为高导热纤维的应用开发提供指导。

如何将纳米尺度的石墨烯、碳纳米管进行有效组装并将其优异的力、电、热等性能在宏观体中充分体现一直高度关注的热点问题。这对其在很多领域的应用具有重大的实际价值与现实意义，比如在高导热纤维材料研究领域。本项目围绕浮动催化法制备碳纳米管纤维技术和石墨烯材料，系统研究了生长参数对碳纳米管自身结构、碳纳米管网络结构及纤维的力、导电、导热性能的影响。项目组系统研究了在碳纳米管网络上原位生长/复合石墨烯，以及将生长得到的碳纳米管套筒经过含有氧化石墨烯的溶液进行纤维化及热处理等两种方式，来实现石墨烯/碳纳米管复合纤维的制备，突破了石墨烯在碳纳米管网络中的可控组装关键技术。对上述复合纤维进行后续牵伸、致密，及高温炭化、石墨化，得到导热性能显著提升的复合纤维，并系统研究了石墨烯/碳纳米管网络复合组装行为及复合纤维在碳化过程中的结构-性能演变规律，实现了高导热、导电性能的石墨烯/碳纳米管复合纤维的可控制备，纤维拉伸强度达到1.4GPa，热导率达到1000W/mK。在本项目资金资助下，项目组还在石墨烯/碳纳米管复合薄膜、高导热厚石墨烯膜、石墨烯功能纤维等方面开展了工作，并取得了不错的结果。在本项目资助下，项目组在Adv Funct Mater， Chem Engin J，Carbon等期刊发表SCI论文11篇，申请中国发明专利5项。