膨胀石墨-碳纤维/尼龙三元导热复合材料制备

Preparation of expanded graphite-carbon fiber/nylon ternary thermally conductive composites

以尼龙6(PA6)为基体,膨胀石墨(EG)和碳纤维(CF)作为导热填料,采用熔融共混法制备了EG/PA6、CF/PA6和CF-EG/PA6导热复合材料。重点研究当固定导热填料(CF和EG)填充量为40wt%时,CF与EG不同的填充比例对CF与EG的接触方式及CF-EG/PA6复合材料的导热性和力学性能的影响。结果表明,相比单一CF填充,EG的加入有利于CF-EG/PA6复合材料热导率的增加;CF∶EG质量比是25∶15时的EG-CF/PA6三元复合材料,热导率可以达到2.554W/(m·K),是PA6的8倍,拉伸强度提高了125.34%,弯曲强度提高了119.8%,同时具有优异的耐热性。SEM结果表明,纤维状CF与蠕虫状EG片层在适当的填充比例下可以形成"面接触"的三维网络结构,这种三维网络结构不仅显著增大EG-CF/PA6复合材料的热导率,而且明显提高了其力学性能和耐热性能。为研制填充型导热高分子材料提供了一条新思路。

With nylon 6(PA6)as the matrix and carbon fiber(CF),expanded graphite(EG)as the thermal conductive filler,EG/PA6,CF/PA6 and CF-EG/PA6 thermal conductive composites were prepared by melt-mixing.Fixed the filling content of 40 wt%,the effects of different ratios of CF to EG on the contact mode between CF and EG,and the thermal conductivity and mechanical properties of CF-EG/PA6 composites were studied.The results indicate that the addition of EG is beneficial to increase of the thermal conductivity of CF-EG/PA6 composites compared to single CF filling;When CF∶EG mass ratio is 25∶15,the thermal conductivity of CF-EG/PA6 composite reaches 2.554 W/(m·K),which is 7 times higher than that of PA6,the tensile strength is increased by 125.34%,the flexual strength is increased by 119.8%,and the heat resistance demonstrates excellent.The SEM results show that fibrous CF and worm-like EG can form a 3 Dnetwork structure with"Terms contact"under the appropriate filling ratio.The 3 Dnetwork structure not only significantly increases the thermal conductivity of CF-EG/PA6 composite,but also significantly improves the mechanical and thermal properties of the composite.It provides a new idea for the development of filled thermally conductive polymer materials.