PMDA is a solid, with a melting point of 284-288°C. It has been around since the 1950s and was initially used as a curing agent for epoxy resins. It is both highly rigid and reactive upon melting. Cured resins have a high glass transition temperature and exhibit brittleness. As a result, the use of PMDA with epoxies has been replaced by other dianhydrides such as BTDA for select applications.