Synthesis and properties of polyimides derived from 1,6‐bis(4‐aminophenoxy)naphthalene and aromatic tetracarboxylic dianhydrides

Abstract

Abstract 1,6‐Bis(4‐aminophenoxy)naphthalene ( I ) was used as a monomer with various aromatic tetracarboxylic dianhydrides to synthesize polyimides via a conventional two‐stage procedure that included ring‐opening polyaddition in a polar solvent such as N,N ‐dimethylacetamide (DMAc) to give poly(amic acid)s, followed by thermal cyclodehydration to polyimides. The diamine ( I ) was prepared through the nucleophilic displacement of 1,6‐dihydroxynaphthal‐ene with p ‐chloronitrobenzene in the presence of K 2 CO 3 , followed by catalytic reduction. Depending on the dianhydrides used, the poly(amic acid)s obtained had inherent viscosities of 0.73–2.31 dL/g. All the poly(amic acid)s could be solution cast and thermally converted into transparent, flexible, and tough polyimide films. The polyimide films had a tensile modulus range of 1.53–1.84 GPa, a tensile strength range of 95–126 MPa, and an elongation range at break of 9–16%. The polyimide derived from 4,4′‐sulfonyldiphthalic anhydride (SDPA) had a better solubility than the other polyimides. These polyimides had glass transition temperatures between 248–286°C (DSC). Thermogravimetric analyses established that these polymers were fairly stable up to 500°C, and the 10% weight loss temperatures were recorded in the range of 549–595°C in nitrogen and 539–590°C in air atmosphere. © 1995 John Wiley & Sons, Inc.