Aromatic Polyethers by Nucleophilic Substitution

Polyetherketones and polyethersulfones, also referred to as polyketones and polysulfones, are synthesized by nucleophilic aromatic substitution between aromatic dihalides and bispheno-late salts [Cassidy, 1980 Clagett, 1986 Critchley et al., 1983 Harris and Johnson, 1989 Jayakannan and Ramakrishnan, 2001 Matsumura et al., 2001 May, 1988], This is shown in Eq. 2-206, where X is halogen and Y is C=0 or S02  

Other reactions have been studied for synthesizing these polymers, including the electrophilic aromatic substitution of acyl and sulfonyl halides on aromatic reactants and the nickel-catalyzed aromatic coupling of aromatic dihalides [Yonezawa et al., 2000]. 

Polymers XL-XLIII are commercially available. XL and XLI are referred to as poly-etheretherketone (PEEK) and polyetherketone (PEK), respectively. XLII and XLIII are known as bisphenol A polysulfone and poly ethersulf one, respectively. Polymers XLI and XLIII can be synthesized not only using the combination of A—A and B—B reactants, but also by the self-polymerization of appropriate A—B reactants. 

The polysulfones are transparent, amorphous polymers but possess good mechanical properties due to the rigid polymer chains. The glass transition temperatures are in the 180-230°C range, and polysulfones are rated for continuous use in the 150-200°C range. 

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HIGH-PERFORMANCE POLYMERS 149 2-14c Aromatic Polyethers by Nucleophilic Substitution... 

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