Synthesis and characterization of isomeric biphenyl‐containing poly(aryl ether bisketone)s, 3. Polymers derived from 3,4′‐bis(4‐fluorobenzoyl)biphenyl and bisphenols

A series of high‐molecular‐weight amorphous and semicrystalline poly(aryl ether bisketone)s were prepared from bisphenols and 3,4′‐bis(4‐fluorobenzoyl)biphenyl via nucleophilic aromatic substitution reactions. Model compound studies were carried out with several substituted monohydric phenols, 3,4′‐bis(4‐fluorobenzoyl)biphenyl and 3,4′‐bis(4‐Chlorobenzoyl)biphenyl. The dihalo‐substituted aromatic ketones were synthesized by the reaction of 3,4′‐biphenyldicarboxylic acid with thionyl chloride, followed by Friedel‐Crafts acylation with the appropriate aryl halide. The required dicarboxylic acid was prepared starting from 4‐bromotoluene and 3‐methylcyclohexanone. Potassium carbonate mediated reaction of the monomers in dimethylacetamide or diphenyl sulfone gave high‐molecular‐weight polymers in excellent yield. The glass transition temperatures of the polymers are in the 170 to 190°C range. In addition, the polymers exhibit excellent thermal stability, as evidenced by both dynamic and isothermal thermogravimetric analysis, and afford tough films by compression molding.