Synthesis and properties of poly(ether imide)s having ortho-linked aromatic units in the main chain

This paper demonstrates the synthesis and characterization of poly(ether imide)s with ortho-linked main-chain units based on the bis(ether anhydride)s derived from catechol and 2,3-dihydroxy-naphthalene. The polymerization was conducted in two steps via the formation of a poly(amic acid) precursor followed by thermal cyclodehydration. The resulting polymers were characterized by inherent viscosity, solubility, film-forming ability, tensile tests, differential scanning calorimetry (DSC), thermogravimetry (TG), and wide-angle X-ray diffraction measurements. Typical poly(ether imide)s were noncrystalline and showed excellent thermal stability. The polymers had glass transition temperatures from 193 to 224 degrees C and exhibited excellent processability. Many poly(ether imide)s were also soluble in dipolar aprotic solvents and m-cresol.