Abstract: The microwave absorbing materials in future are characterized by thin thickness，light mass，wide range，strong absorption，and are required to endure high temperature，oceanic weather，nuclear radiation and so on.Polyparaphenylene and its derivatives，especially doped conducting polymer，might become a new kind of microwave absorbing materials owing to its easy preparation，good environmental stability and high microwave absorption.LiNi-ferrite powders could be used as microwave absorbers for X-band frequencies because of its high magnetic anistropic.The conducting polyaniline/LiNi-ferrite nanocomposites possess both dielectric losses and magnetic losses，so they have good application prospect in radar absorbing materials.Polyparaphenylene/LiNi-ferrite nanocomposites were prepared by a novel rheological phase reaction method.The effect of spark plasma sintering (SPS)conditions on electrical conductivity and thermal conductivity was investigated.The TEM images show the size of LiNi-ferrite is around 100-300 nm and the polyparaphenylene disperses in the oxide matrix evenly not only on the grain boundaries，but also inside the grains.It was found that the electrical conductivity of nanocomposites do not change with sintering conditions whereas the thermal conductivity increase with sintering conditions.With sintering times increasing，the size of LiNi-ferrite becomes large.The growing of LiNi-ferrite makes mean free path of phone and lattice thermal conductivity increase.The thermal conductivity increases with lattice thermal conductivity increasing.Because of the poor electrical conductivity of LiNi-ferrite，the growing of LiNi-ferrite has no effect on the electrical conductivity of nanocomposites.

Key words: polyparaphenylene, LiNi_0.5Fe₂O₄, nanocomposites, electrical conductivity；thermal conductivity

摘要： 以溶剂热法合成聚对亚苯基/LiNi_0.5Fe₂O₄纳米复合材料，分别对放电等离子烧结时不同保温时间制备的样品的电导率和热导率进行了研究。发现，保温时间不同对聚对亚苯基/ LiNi_0.5Fe₂O₄纳米复合材料的电导率没有明显的影响，但对热导率具有一定的影响，保温时间越长热导率越大。保温时间延长，导致铁氧体晶粒长大，使材料体系的声子平均自由程增加，因此声子热导率增加，从而导致总热导率的增加。由于铁氧体具有较差的电输运特性，因此晶粒长大对电导率大小没有明显的影响。

关键词: 聚对亚苯基, LiNi_0.5Fe₂O₄, 纳米复合, 电导率, 热导率