氮化硼和纳米金刚石混杂填充聚酰亚胺导热复合材料的制备与表征

以二维六方氮化硼和三维纳米金刚石为导热填料通过原位聚合方式杂化填充到聚酰亚胺(PI)基体中制备导热绝缘复合材料。采用聚芳酰胺和4,4-二氨基二苯醚分别对氮化硼和纳米金刚石进行表面接枝改性,以提高有机-无机两相界面的相容性。通过扫描电子显微镜、导热仪、热重分析等方法对复合材料的结构和性能进行了表征。结果表明,不同粒径的导热填料混杂填充聚合物,利用协同效应可以提高堆砌密度,降低界面热阻,形成导热网络。当填料总质量分数为30%,改性氮化硼和纳米金刚石的质量比为9∶1时,复合材料的热导率达0.596 W/(m·K),是纯PI的3.5倍,同时复合材料仍具有较好的热稳定性和电绝缘性,满足微电子领域的应用需求。

Preparation and Characterization of Surface Modified Boron Nitride/Diamond Polyimide Composites with Enhanced Thermal Conductivity

A novel kind of thermally conductive and outstanding insulation composite was prepared using the mixture of 2-D micro-scale hexagonal boron nitride (h-BN) and 3-D nano-scale diamond (ND) hybrid fillers on the matrix of polyimide (PI) by in-situ polymerization.In order to improve the interfacial compatibility between the inorganic filler and the polymer matrix,BN fillers were functionalized with aromatic polyamide (HBP) and ND particles with 4,4'-oxybisbenzenamine (ODA).The structure and properties of the composites were characterized by scanning electron microscopy (SEM),thermo-gravimetric analysis (TGA) and thermally conductive instrument.The results indicate that the thermal conductivity of the composite can be enhanced with different sizes and types of the fillers,because of increasing the packing density,reducing the interfacial thermal resistance and forming thermal conductive networks.When the filler content is 30 ％ with the HBP-BN and ND-ODA mass ratio of 9:1,the thermal conductivity of the composite is 0.596 W/(m· K),3.5 times higher than that of the neat PI.Meanwhile,the composites fabricated possess excellent electrical insulation and thermal stability,and may be appropriate for application of the electronic materials.