为了降低聚合物基导热复合材料中填料的含量，用聚酰胺6(PA6)／聚丙烯(PP)两相聚合物作为基体，研究了PA6／PP／鳞片石墨(FG)和PA6／FG复合材料的热导率随FG含量的变化规律。PA6／FG复合材料中FG质量分数为30%时，复合材料的热导率为1.85 W／(m·K)，而PA6／PP／FG复合材料热导率达到1.88 W／(m·K)时，FG的质量分数仅需20%，说明PP作为体积排除相，优化了FG在PA6中的分布。以PA6／PP作为基体，达到与PA6单一基体相近的热导率时可以降低FG的填充量，改善导热复合材料的加工性能和力学性能。同时研究了不同FG含量下两种复合材料的电阻率，结果发现，在FG质量分数为30%时，PA6／PP／FG复合材料的体积电阻率比PA6／FG的体积电阻率低两个数量级，间接证实PP的加入改变了FG在PA6中的分布。用扫描电子显微镜对FG在PA6／PP／FG复合材料中的分布进行了研究，结果表明，当FG质量分数超过30%时，FG相互之间的接触增多。%Polyamide 6(PA6)/polypropylene(PP) as a two-phase polymer matrix was used to reduce the filler content of thermally conductive composites based on polymer materials. Thermal conductivities of both PA6/PP/flake graphite(FG) and PA6/FG composites with different FG content were studied. Thermal conductivity of PA6/FG composite is 1.85 W/(m·K) when FG content is 30%;while thermal conductivity of PA6/PP/FG composite could reached to 1.88 W/(m·K) as long as FG content is 20%. This implies that PP as a size-exclusion phase could optimize the distribution of FG in PA6. FG content could be reduced when thermal conductivities of PA6/PP/FG composites reach to the same value as PA6/FG composites, thus could improve the processing performance and mechanical properties of thermally conductive composites. Electrical resistivities of PA6/PP/FG and PA6/FG composites were also studied. The results show that the volume electrical resistivity of PA6/PP/FG composite is two orders of magnitude lower than PA6/FG composite when FG content is 30%. This indicates that the addition of PP changes the distribution of FG in PA6. The distribution of FG in PA6/PP/FG composite was studied by SEM. It showes that the possibility of FG contact with each other is increased when the content exceeds 30%.
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