Mechanism of endo-exo isomerization of nadimide end-capped oligomers

Abstract

Before polymerization, nadimide end-capped polyimide oligomers exist in the endo form. During the cure, an endo-exo equilibrium takes place. This paper discusses the relationship between endo-exo isomerization and the reverse-Diels-Alder reaction of the nadinaide system. As a consequence of the experimental results, an explanation for cyclopentadiene evolution during the polymerization of nadimide systems is given.