碳纳米管海绵导热性能的实验研究

Experimental Study on Thermal Conductivity of Carbon Nanotube Sponges

为了实现资源可持续性发展,保温材料的使用成为当代社会生产节能的重要手段。基于碳纳米管的三维宏观体——碳纳米管海绵,其立体空心网状塔接结构使得碳纳米管海绵具有良好的保温性能和热稳定性。显然,碳纳米管海绵的导热性能实验研究可以为该新型材料的应用提供相应的数据支持,并且对满足社会生产需求意义重大。通过实验室针对一维材料热扩散系数的表征方法——瞬态电热(TET)测量技术,对碳纳米管海绵材料进行室温下热扩散系数的测量,借助Schuetz多孔介质导热模型得到样品的骨架导热率为45~51 W·m^(-1)·K^(-1),而真实导热率达到了0.15 W·m^(-1)·K^(-1)。最后,从微尺度传热的角度解释了碳纳米管海绵的热运输机理,并通过SEM照片证实了碳纳米管海绵结构缺陷会使得样品表面声子散落和接触电阻增大,从而导致了碳纳米管海绵的低导热性能。

In order to achieve the sustainable development of resources,the use of thermal insulation materials has become an important means of energy conservation in contemporary society.Due to the three-dimensional(3D)porous network structure,carbon nanotube sponges(CNT sponges)have excellent thermal insulation performance and thermal stability.Obviously,the experimental study on thermal conductivity of CNT sponges will provide a favorable database for the application of this new thermal insulation material,which is of great significance to meet the needs of social production.Therefore,this paper reports on a thermal diffusivity of CNT sponges at room temperature using the transient electro-thermal(TET)measurement technology,and this measurement method is specially aimed at the thermal characterization of micro-nano scale materials.By Schuetz's thermal conductivity model,the skeletal thermal conductivity of CNT sponges is determined at 45~51 W·m^(-1)·K^(-1),and the real thermal conductivity reached 0.15 W·m^(-1)·K^(-1).Finally,the thermal transport mechanism of CNT sponges was explained from the perspective of micro-scale heat transfer,and the SEM images proved that the structure defect of CNT sponges would bring about the influence of phonon scattering on the sample surface and the increase of contact resistance,thus resulting in the low thermal conductivity of CNT sponges.