BPDA is a biphenyl tetracarboxylic dianhydride monomer, mainly used in the production of special materials such as polyimide. Polyimide is a high-molecular compound prepared through a polymerization reaction of dianhydride and diamine compounds. It has outstanding temperature resistance and excellent mechanical properties, and is currently the polymer material with the best heat resistance that can be actually used on a large scale. It is widely applied in emerging fields such as aerospace, electrical insulation, flexible display, new energy, and microelectronics.