Synthesis and properties of poly (ether imide)s derived from dihydroxynaphthalenes

Abstract

Polyether imide's were synthesized from bisfether anhydride's derived from 1,5-, 2,3-, 2,6- and 2,7-dihydroxynaphthalenes and various aromatic diamines using a two-stage solution process, normally with chemical imidization. During the synthesis of polymers from the bis (ether anhydride) from 2,3-dihydroxynaphthalene and 4,4′-oxydianiline (4,4′-ODA), by both chemical and thermal imidization, small proportions of a relatively insoluble, infusible, crystalline solid were produced. It is proposed that this product is a cyclic oligomer. Solubilities of the polymers were assessed and, where sufficiently soluble, molecular weights were determined by gel permeation chromatography. Apart from polymers based on 2,3-naphthalene units, the polymers had limited solubilities. Glass-transition temperatures were determined; all were in excess of 220 °C, some were in excess of 300 °C. Several poly(ether imide)s based on ODA, were found to be thermally stable to 590 °C. Polymers based on the bis(ether anhydride) derived from 2,3-dihydroxynaphthalene gave strong solvent-cast films with high moduli extensions to break were modest except for the polymer from the diamine BAPB which extended to 150% prior to fracture.