Soluble aromatic poly(ether ketone)s with a pendant 3,5-ditrifluoromethylphenyl group

A novel bisphenol monomer, (3,5-ditrifluoromethyl)phenylhydroquinone (6F-PH), was synthesized in a three-step synthetic procedure. Three aromatic poly(ether ketone)s (PEKs) based on 6F-PH were prepared via a nucleophilic aromatic substitution polycondensation with three difluorinated aromatic ketones. These PEKs had a high thermal stability, and the temperatures at the 5% weight loss are above 532 degreesC in air. The solubility of the PEKs was improved by the introduction of bulky pendant groups. All the polymers formed transparent, strong, and flexible films with tensile strengths of 86.2-99.5 MPa, Young's moduli of 2.32-3.24 GPa, and elongations at break of 11-14%. These PEK films have low dielectric constants of 2.68-2.89 at I MHz and low water absorptions of 0.29-0.47%. (C) 2004 Elsevier Ltd. All rights reserved.