环氧树脂中3D氮化硼复合导热网络的构筑及性能

Constructing of 3D Micro-Nano Boron Nitride Networks in Epoxy Resin and Characterization

采用聚苯乙烯(PS)微球为模板,与不同尺寸六方氮化硼(h-BN)混合,经过热压成型、烧蚀致孔和浸润环氧等步骤制备了具有3D氮化硼导热网络结构的氮化硼/环氧树脂复合材料。扫描电镜观察表明,氮化硼在环氧树脂中形成了连续的导热网络,且不同尺寸氮化硼之间的复配显著增加了导热网络的完善程度,复合材料的导热系数大幅提高,当h-BN(15μm)∶h-BN(1μm)=9∶1(体积比,下同),有效导热系数达到1.98 W/(m·K),热膨胀系数降低到43.27μm/(m·℃)。同时,复合材料的热稳定性、介电性能、动态力学性能等都有所提升。

In this paper, polystyrene (PS) microspheres were used as template and mixed with different sizes of hexagonal boron nitride(h-BN) to construct the 3D boron nitride network structure in the epoxy resin. The 3D structure was prepared by hot compression, ablation, and then infiltrated with epoxy resin. The SEM observation shows that continuous thermal conductive networks of boron nitride were formed in the epoxy resin, and composites with different sizes of boron nitride possess a significant increase in the density of thermal networks, the thermal conductivity of composite is greatly improved. When the ratio of h-BN (15 μm) and h-BN (1 μm)is 9∶1 (the volume fraction is 50%), the highest thermal conductivity (1.98 W/(m·K)) could be exhibited, the thermal expansion coefficient reduces to 43.27 μm/(m·℃). Meanwhile, the thermal stability, dielectric performance and dynamic mechanical properties of the composite materials are also improved.