聚酰亚胺/二氧化硅杂化膜的制备与介电性能的研究

Preparation and Study on the Dielectric Properties of Polyimide/silica Hybrid Films

采用溶胶-凝胶法制备了BTDA-ODA聚酰亚胺/SiO2杂化膜,利用红外分光光度计(FTIR)、热重分析仪(TGA)和透射电镜(TEM)研究了杂化膜的微观结构和热性能,并对杂化膜的介电常数(e)和介电损耗(tand)随SiO2粒子含量和电场频率的变化进行了分析和讨论。结果表明:杂化膜的介电常数和介电损耗随SiO2粒子含量的增加而增大,随电场频率的升高而逐渐降低,用考虑到粒子的形状因素和两相间相互作用的EMT模型可以预测聚酰亚胺/SiO2杂化膜的介电常数。

PI/SiO2 hybrid films were prepared with an improved sol-gel process, Fourier transform infrared spectroscopy （FT-IR）, transmission electron microscope （TEM） and thermal gravimetric analysis （TGA） were used to characterize the structure and properties of the obtained films. Changes of dielectric constant （e） and dielectric loss （tand） with silica content and the frequency of applied alternating field have been discussed. The results showed that the dielectric constant （e） and the dielectric loss （tand） of the composites increased with the increasing the volume fraction of SiO2 particles, and decreased slightly with increasing the frequency of applied alternating field. The polymide/SiO2 was used to explore the valid of some mathematic models for predicting the dielectric constant of two-phase composite. The EMT model was proved to be a good tool to predict the dielectric constant of the composites.