Pyromellitic dianhydride, pure products are white or slightly yellow crystals. Exposed to moist air will quickly absorb moisture from the air and hydrolyzed into Pyromellitic Acid. Dissolved in dimethyl sulfoxide, dimethylformamide, acetone and other organic solvents, insoluble in ether, chloroform and benzene. Mainly used as raw material for polyimide, and crosslinking agent for the manufacture of epoxy curing agent and the polyester tesin extinction.