Effects of coupling agents on structure and properties of polyimide/nano-alumina hybrid films

Polyimide/nano-alumina hybrid films were prepared via ultrasonic-mechanical method, and the nano-alumina powders were treated by different coupling agent, then dispersed them homogenously in polyamic (acid) by some modes under the assistant of ultrasonic wave. The micro-morphology of PI hybrid films and order degree of polyimide molecular were characterized by SEM and X-ray diffraction spectra. The thermal stability, mechanical properties and electric breakdown strength of PI hybrid films were tested. The results indicated that the coupling agents had effects on the order degree of polyimide molecular. In the PI/nano-Al₂O₃ hybrid films, the nano-alumina was treated by four kinds of coupling agent, the PI hybrid film with KH550 had the optical thermal stability and mechanical properties, and the electric breakdown strength of the PI hybrid film with AE3012 was the best.