Geoffrey C. Eastmond

Synthesis of bulky bis(ether anhydride)s and poly(etherimide)swith bulky main-chain units

A series of bis(ether anhydride)s has been synthesized from very bulky bisphenols. Poly(ether imide)s have been synthesized from these bis(ether anhydride)s and two diamines in order to provide a series of poly(ether imide)s with bulky main-chain units. The polymers have been characterized in terms of molecular weight, solubility, glass-transition temperature and thermal stability in order to identify a series of high-performance polymers which are processable and potentially useful for applications which require soluble poly(ether imide)s for fabrication into, for example, gas separation membranes.

Synthesis of bis(ether nitrile)s and bis(ether acid)s from simplearomatic diols bymeta-fluoro displacement from3-fluorobenzonitrile

There is interest in synthesizing bis(ether acid)s and related compounds to use as monomers in order to prepare processable aromatic polymers, such as poly(ether amide)s and poly(ether ester)s. We have now found that it is possible to prepare efficiently bis(3-cyanophenoxy)phenylenes by fluoro displacement from 3-fluorobenzonitrile and phenylene diols or their derivatives, such as substituted catechols, and to convert those bis(ether nitrile)s to bis(3-carboxyphenoxy)phenylenes which can be used in the synthesis of poly(ether amide)s and poly(ether ester)s. Themeta-fluoro displacement is performed at elevated temperatures in N-methylpyrrolidinone.

Nitrodisplacement reactions and the synthesis of bis (ether anhydride) s from dihydroxynaphthalenes

Nitrodisplacement reactions between all ten dihydroxynaphthalenes and 4-nitrophthalodinitrile have been studied. Apart from 1,8-dihydroxynaphthalene, all dihydroxynaphthalenes undergo nitrodisplacement but only 1,5-, 2,3-, 2,6- and 2,7-dihydroxynaphthalenes give high yields of pure bis(ether dinitrile). The bisfether dinitriles produced in high yield were hydrolysed and converted to bis(ether anhydride) for subsequent synthesis of poly(ether imide)s. Success in nitrodisplacement correlates with high redox potentials for the dihydroxynaphthalenes, except for 1,8-dihydroxynaphthalene which probably fails to react because of steric constraints at the peri positions.

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

Polyether imides were synthesized from bisfether anhydrides 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.