Dithioacetalisation of PEEK: a general technique for the solubilisation and characterisation of semi-crystalline aromatic polyketones

Abstract

The family of semi-crystalline, aromatic, high-temperature thermoplastics known as poly(ether-ketone)s are insoluble in conventional organic solvents, but undergo completely general and quantitatively reversible reactions with alkanedithiols in strong acid media, to give soluble poly(dithioacetal)s, which are readily characterisable by GPC and light scattering techniques.

Synthesis and characterization of soluble poly(arylene ether ketone)s with high glass transition temperature based on 3,6-bi(4-fluorobenzoyl)-N -alkylcarbazole

“…Turner and colleagues and Colquhoun et al . had previously reported studies on the structure and molecular weight respectively of insoluble polyetheretherketone (PEEK) by MALDI‐TOF, wherein soluble PEEK oligomers or soluble modified PEEK derivative‐like poly(ether dithioketal) were used as the model . However, the appropriate models of 10a have not been found so far for structure analysis because the MALDI‐TOF technique favors the ionization of soluble low molecular weight species .…”

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

“…Preliminary studies showed that prolonged reactions (18)(19)(20) Analysis of poly(ether ketal)s by 1 H NMR spectroscopy showed no detectable dithioketal residues, but deprotected ketonic units were present at levels of between 5 and 45 mole%. Both PEEK-1,3-dithiolane (1) and PEEK-1,3-dithiane (2) successfully participated in this reaction, forming the same end-products.…”

“…9-14 Amongst the first efforts was that of Kelsey et al, 14 With specific relevance to the present work, a further novel approach to fully-reversible derivatisation of poly(arylene ether ketone)s has been reported. 18,19,20 The carbonyl groups were protected by reaction with dithiols such as 1, The dithioketalization approach offers a general, non-degradative pathway for reversible chemical modification of any poly(arylene ether ketone). However, removal of the dithioketal group is generally slow and difficult (though achievable), 19 chemistry, cyclic dithioketals are also difficult to hydrolyze but they do participate in exchange reactions, for example with ethane-1,2-diol or 2-mercaptoethanol in the presence of a catalyst such as mercury(II) chloride, yielding the corresponding 1,3-dioxolanes or 1,3-oxathiolanes.…”

Preparation of a novel phosphorus–nitrogen flame retardant and its effects on the flame retardancy and physical properties of polyketone

“…In addition, aliphatic PK is a semicrystalline thermoplastic that exhibits superior mechanical properties, barrier properties, and high temperature and chemical resistance. Due to these characteristics, aliphatic PK can be used for various applications, such as barrier packaging, engineering, and as fiber . However, despite its high thermal stability, the combustibility of aliphatic PK restricts its applications.…”