And transetherification

The package stability of alcohol-soluble resole resins and their compatibility with epoxy resins can be improved by partial conversion of the methylol groups to ethers. Allyl ethers have been used with epoxy resins in interior can coatings. Low molecular weight butyl ethers are used with acid catalysts to cross-link epoxy resins and other hydroxy-substituted resins, by etherification and transetherification reactions (148). 

One drawback of the nucleophilic routes described so far is that they produce a metal salt and solid solvent residue which needs to be removed from the system. In many condensation polymerisations the small molecule produced is volatile and can be removed directly from the reaction. The KF residue leads to reversibility of the reaction and transetherification. However, the low solubility of KF in diphenylsulfone means that a high molecular weight can still be achieved and the KF can be removed by extraction with water. Indeed extraction with water at very high temperatures has recently been used to produce ultrahigh-purity grades of PEEK [10]. These materials can have less than 1 ppm residual potassium and sodium. 

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See also in sourсe #XX -- [ ]

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