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

Abstract

A series of high-molecular-weight amorphous and semicrystalline poly(ary1 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-~hlorobenzoyl)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. Scheme I: