Polyketone Synthesis Involving Nucleophilic Substitution via Carbanions Derived from Bis(α-amino nitrile)s. 2. Wholly Aromatic Polyketones without Ether Linkages

Abstract

To address the insolubility problem of polyketones, we used a new approach to high molecular weight wholly aromatic polyketones without ether linkages via soluble precursors derived from isophthaldehyde-based amino nitriles. 1 High molecular weight, soluble poly(amino nitrile)s 2 were synthesized from the anions of these bis(amino nitrile)s 1 and 4,4′-difluorobenzophenone using sodium hydride as base under mild reaction conditions. Hydrolysis of the poly(amino nitrile)s under acidic conditions yielded the corresponding polyketone, poly(p-phenylenecarbonyl-p-phenylenecarbonyl-mphenylenecarbonyl) (3). This all aromatic polyketone, with an absence of ether linkages in the polymer backbone, displays excellent thermal properties and solvent resistivity. It is infusible and insoluble in most common organic solvents.

Thermally curable fluorinated main chain benzoxazine polyethers via Ullmann coupling

“…In this connection, it should be pointed out that 'Ullmann type condensation' of the 'dibromo monomers' with bisphenol-A and bisphenol-AF also yields aromatic polyethers with similar low molecular weights. 53,54 Moreover, both TetradecaF-PolyBenzPre and OctaF-Poly-BenzPre have higher yields and higher molecular weights compared to nonF-PolyBenzPre and HexaF-PolyBenzPre. The main reason for these results is the activity of uorine groups on the highly uorinated monomers compared to lower F containing ones.…”

Exchange Reactions of Poly(arylene ether ketone) Dithioketals with Aliphatic Diols: Formation and Deprotection of Poly(arylene ether ketal)s

“…Hydrolysis of PEEK-1,3-dioxolane 6, the most stable of the PEEK-based ketals obtained in this work, was therefore next investigated. Previous reports of heterogeneous hydrolysis of a PEK-1,3-dioxolane copolymer (50% ketone, 50% dioxolane), together with 13 cleavage under homogeneous conditions in concentrated sulfuric acid, were given by Kelsey et al 10 In the present work, PEEK-1,3-dioxolane 6 was dissolved in dichloromethane or chloroform at room temperature and concentrated aqueous HCl (37%) or 100% trifluoroacetic acid (TFA) was then added (Scheme 4). With TFA, the resulting PEEK remained in solution and was recovered by precipitation in methanol, but with HCl, PEEK crystallized out after 20-30 minutes because 37% HCl aq is not a sufficiently strong acid to retain the polyketone in solution.…”

Synthesis of thermally robust benzimidazolone-based wholly aromatic polyketones

“…Aromatic polymers containing only aromatic rings and ketonic carbonyl groups as dominating linkages in the main chain are defined as wholly aromatic polyketones. 1 The structural characteristics of the wholly aromatic polyketone endowed the polymer with longer conjugating units than poly(aryl ether ketone)s (PAEKs), which are an important class of high performance resins. In the main chain of PAEK, the ether bond was a weaker linkage compared to the carbonyl group.…”