Pyromellitic dianhydride

UsesPyromellitic dianhydride (PMDA) is employed as a curing agent for epoxy agent resins used for casting, laminating, the manufacture of moulding powders, adhesives and coatings.

UsesPyromellitic dianhydride is used as a monomer in the preparation of polyimide polymers such as kapton; thermoplastics such as polyesters, polyethers, plasticizers, and expoxy resins. It is involved in the preparation of high performance coatings due to its mechanical, thermal and oxidative stability properties. It acts as a curing agent for epoxy resins which find application in adhesives, coatings and molding powders. As an intermediate, it plays an important role in polyimide based materials like printed circuit boards, tape automated bonding and magnetic wire insulation.

General DescriptionPyromellitic dianhydride (PMDA) is an acidic anhydride that can be used as a repair agent and as a chain extender in the formation of polyethylene terephthalate (PET) based chain extensions. It is mainly used in the production of thermoplastics and other coating applications.

PreparationPyromellitic Dianhydride is prepared by gas-phase oxidation of 1,2,4,5-tetramethylbenzene (or related tetrasubstituted benzene derivatives). An idealized equation is:C6H2(CH3)4 + 6 O2 → C6H2(C2O3)2 + 6 H2OIn the laboratory, it can be prepared by dehydration of pyromellitic acid using acetic anhydride.