Alicyclic polyimides: An approach from monomer synthesis

Polyimides obtained from dianhydrides and diamines by the polycondensation are classified into four distinct categories according to the chemical structure of the monomers. Aliphatic polyimides derived from aliphatic monomers are soluble in organic solvents and form the colorless and flexible films, whereas most of fully aromatic polyimides such as Kapton(R) are insoluble and absorb visible light. Especially, alicyclic monomer based polyimides have attracted much attention in recent years because of their potential applications including use as liquid crystal orientation layers or low dielectric materials. In this review, a historical aspect and recent advances in the polyimide synthesis are described with particular focus and emphasis on the monomer synthesis using the Diels-Alder reaction, the Pd-catalyzed methoxycarbonylation and so on.