Novel High T_g High-Strength Poly(aryl ether)s

Abstract

A novel 2-perfluoroalkyl-activated bisfluoro monomer has been synthesized successfully using a Pd(0)-catalyzed cross-coupling reaction of 4-fluoro-3-trifluoromethyl phenyl boronic acid with 4,4'-dibromodiphenylbenzene. This monomer was converted to novel poly(aryl ether)s by nucleophilic displacement of the fluorine atoms on the benzene ring with several bisphenols. The products obtained by displacement of the fluorine atoms exhibit weight average molar masses up to 1.06 × 105 g·mol-1 in GPC. These poly(aryl ether)s showed outstanding thermooxidative stability up to 534 °C for 5% weight loss in TGA under synthetic air and high glass transition temperatures (Tg) even up to 300 °C in DSC and DMTA. These polymers are soluble in a wide range of organic solvents, e.g., CHCl3, THF, NMP, DMF, toluene, etc., and are insoluble in DMSO and acetone. Transparent thin films of these polymers cast from DMF exhibited tensile strengths up to 115 MPa, moduli up to 2.59 GPa, and elongations up to 120% depending on their exact repeating unit structures. These values are comparable to those of high performance thermoplastic materials such as PEEK or Ultem PEI.