SiO2含量对PTFE/SiO2复合材料性能的影响

采用类似于粉末冶金工艺,制备了无定形SiO2填充聚四氟乙烯(PTFE)复合材料,并对其进行了热、介电性能测试和SEM分析表征。系统研究了(1-x)PTFE-xSiO2(x为质量比)复合介质材料中,不同x值(x=0.35,0.40,0.45,0.50,0.55)对材料结构和性能的影响。结果表明,复合材料的密度随着SiO2含量的增加而减少,吸水率、热膨胀系数、介电常数和介电损耗随着SiO2含量的增加而增加。当SiO2质量分数为50%时,PTFE能很好地在SiO2表面形成一层包覆层,此时复合材料具有合适的热膨胀系数(17μ℃-1)、介电常数(2.74)和低介电损耗(0.002)。

Effects of SiO2 Content on the Properties of PTFE/SiO2 Composites

The amorphous SiO2 filled PTFE composite materials were prepared by using the technology similar to the powder metallurgy.The thermal and dielectric properties of the composites were measured.Also,the microstructure evolution of the composites was characterized by the scanning electron microscopy(SEM).The effects of the different xvalue(xis the mass ratio,x=0.35,0.40,0.45,0.50,0.55) on the microstructure and dielectric properties of(1-x) PTFE-xSiO2 composite dielectric material were investigated.It was found that the density of the composite decreased as the content of SiO2 increased.On the other hand,the water absorption,thermal expansion coefficient,dielectric constant and dielectric loss were increased with the SiO2 content increasing.When the content of SiO2 reached 50%,PTFE could be well coated by the SiO2layers,and the composites showed suitable thermal expansion coefficient(17 μ ℃-1),dielectric constant(2.74) and low dielectric loss(0.002 4).