片状Al_2O_3对Al_2O_3/FEP复合材料热导率的影响

Effects of alumina platelets on thermal conductivity of Al_2O_3/FEP composite

通过混炼工艺制备了片状Al2O3填充聚全氟乙丙烯(FEP)复合材料,以颗粒状Al2O3为对比样品,研究了片状Al2O3形状和尺寸对FEP基复合材料热导率的影响,利用SEM观察了FEP基复合材料的微观形貌。结果表明:在低填充量下,Al2O3颗粒在FEP基体中呈"海岛"状分布,没有形成连续的导热网链,但其热导率明显提高;复合材料拉伸强度与断裂伸长率随Al2O3含量的增加而减小;低填充量时复合材料热导率的提高主要来自Al2O3的微细片状结构,这种微细片状结构一方面提高了有效导热路径,另一方面增加了颗粒与基体之间接触面积,因此有利于热导率的提高。

FEP-based composites filled with alumina platelets were prepared by the physical blending method.The thermal conductivity and elongation of the composites containing Al2O3 platelets were studied in comparison with Al2O3 particles as filler.The microstructure of the composites was also observed by SEM.The results show that the Al2O3 fillers with low mass fractions display an island distribution in the FEP matrix and cannot form the continuous thermal conduction chains.However,the thermal conductivities of the composites greatly increase compared with the single FEP.The tensile strength and the elongation at break of the composites decrease with the increase of the Al2O3 content.The increasing thermal conductivity of the composites containing fine alumina platelets is associated with the prolonged heat conducting path and the interface between the fillers and FEP.