两种石墨烯修饰的复合热界面材料的制备及热性能的研究

采用化学氧化还原法制备的石墨烯和化学气相沉积法制备的三维网状石墨烯共同作为导热填料改性环氧树脂,研究导热填料质量分数的变化对环氧树脂热导率的影响,并进一步测定复合热界面材料的热导率在高温下的稳定性。结果表明:当石墨烯-三维网状石墨烯的质量分数为0.2(石墨烯和三维网状石墨烯的比例为1∶9)时,可使环氧树脂的热导率提高2 400%;三维网状石墨烯的三维网状结构和石墨烯的表面官能团对复合热界面材料的热性能具有显著地影响;三维网状石墨烯为声子提供了快速传输通道,而石墨烯的表面官能团能促进环氧树脂与石墨烯之间形成良好的接触,降低界面热阻,在石墨烯和三维网状石墨烯的协同作用下可提高热界面材料的热导率。此外,可以通过优化导热填料的尺寸,提高复合热界面材料热导率的稳定性。

The research of the preparation and thermal performance of two kinds graphene modified epoxy resin

Reduced graphene oxide (RGO) nanosheets and 3D graphene networks (3DGNs) are adopted as co-modifier to improve the thermal performances of epoxy resin (ER), and the influence of mass fractions of the fillers on the thermal conductivity of the resulting composite thermal interface materials (TIMs) is measured. The results demonstrate that a remarkable enhancement (2 400% for the thermal conductivity) can be achieved when the mass fraction of RGO-3DGNs reaches 0.2(ratio of the RGO and 3DGNs is 1:9). Moreover, both the 3D construction of the 3DGNs and surface functional groups of the RGO exert a significant effect on the thermal performance of the interface materials. The 3DGNs provides a fast transport channel for phonons, and surface functional groups of RGO promote the contact between ER and graphene, so they work together to reduce thermal resistance and improve the thermal conductivity of thermal interface materials. In addition, the stability of thermal conductivity of these TIMs can be improved by optimizing the average size of the RGO filler.