Characterization of Gamma‐Ray‐Irradiated Polyimide Flyer and Effect of Electric Explosion Driving Velocity

ABSTRACT Polyimide is one of the most widely used flyer materials for explosive foil initiators, due to its high temperature resistance, outstanding mechanical properties, light weight, and excellent dielectric properties. When polyimide flyers are in service, they will inevitably encounter extreme environments such as gamma rays, resulting in reduced function. In this study, the gamma irradiation effect was studied for polyimide (PMDA‐ODA) flyers, which are spin‐coated and solidified on patterned copper film. The chemical structure of the flyers after gamma irradiation was observed by XPS and FTIR. XPS analysis shows that when the irradiation dose is greater than 3.6 MGy, the carbon atom percentage of polyimide flyers decreases and the oxygen atom percentage increases, which indicates that the surface molecular structure of polyimide flyers changes. The insulation properties of the polyimide flyers were evaluated by the breakdown voltage and dielectric loss factor. The results show that the insulation properties of the flyers are obviously reduced by gamma‐ray irradiation. Further tests of electrical explosion performance show that the velocity of polyimide flyers decreases by 3.4% on average after high‐dose irradiation of 72 MGy. These results will provide important guidance for the design of new flyer materials and the radiation protection of explosive foil initiators.