Synthesis and properties of polyimides derived from 4,4′‐(2,7‐naphthylenedioxy)dianiline and aromatic tetracarboxylic dianhydrides

Abstract

AbstractNovel polyimides containing 2,7‐diphenoxynaphthalene moieties were prepared from 4,4′‐(2,7‐naphthylenedioxy)dianiline (DAPON) and various aromatic tetracarboxylic dianhydrides via a two‐stage procedure that includes ring‐opening polyaddition in a polar solvent such as N,N‐dimethylacetamide to give poly(amic acid)s, followed by cyclodehydration to polyimides. The poly(amic acid)s exhibit inherent viscosities between 0,63 and 1,94 dL/g depending on the tetracarboxylic dianhydrides used. Except for the polyimide 4d, obtained from 3,4 : 3′,4′‐benzophenonetetracarboxylic dianhydride (2d), all polymides from yellow, flexible, and tough films upon casting from the poly(amic acid) solutions. Polyimide 4ederived from 4,4′‐sulfonyldiphthalic anhydride (2e) exhibits better solubility than the other polymides. The polyimides synthesized from and 2d are semicrystalline polymers, whereas the other polyimides are amorphous due to their X‐ray diffractograms. Tensile strength and elongation of the DAPON‐based polyimide films from 86–107 MPa and 6–25% respectively. These polyimides have glass transition temperature 223 and 285°C. Thermal analyses indicated that these polymers are fairly stable, and the 10% weight loss temperatures were recorded in the ranges 568–581 °C in nitrogen and 557–570°C in air.