The fabrication and properties of polyimide/silica-alumina hybrid film

As an engineering material, polyimides(PI) have been extensively applied in many areas such as microelectrics, electric industries and aerospace etc. In this paper, some polyimide/sailica-alumina hybrid films were fabricated using silicon and aluminum sols obtained by sol-gel method. The microstructure, mechanical properties, thermal stability and dielectric properties of hybrid film were investigated. Results indicate that the mechanical properties of PI hybrid film are improved by the addition of SiO2 and Al2O3 due to the formation of fibre structure of inorganic phases. Compared with the plain polyimide, the hybrid films have a higher thermal stability. Relation of dielectric constant and dielectric loss angle with frequency in the hybrid films accordes with Debye relaxation polarization mechanism.