Synthesis and characterization of novel organosoluble poly(aryl ether ketone)s and poly(aryl ether ketone sulfone)s containing 1,4-naphthylene units

Abstract

Two monomers containing naphthalene, 4,4′-di(1-naphthoxy)benzophenone (DNOBN) and 4,4′-bis(1-naphthoxy)diphenyl sulfone (BNODPS), were prepared by the condensation reactions of 4,4′-difluorobenzophenone and 4,4′-dichlorodiphenyl sulfone with 1-naphthol, respectively. Novel poly(aryl ether ketone)s (PAEKs) and poly(aryl ether ketone sulfone)s containing 1,4-naphthylene units were synthesized from DNOBN and BNODPS via the electrophilic Friedel–Crafts acylation polycondensation with various aromatic diacid dichlorides, in the presence of anhydrous aluminum chloride and N-methyl-2-pyrrolidone in 1,2-dichloroethane. Because of the incorporation of 1,4-naphthylene units, the resulting PAEKs and poly(aryl ether ketone sulfone)s exhibited outstanding thermal stability and improved solubility in common organic solvents. The glass transition temperatures are above 200°C, and the temperatures at a 5% weight loss are above 548°C under nitrogen atmosphere. All these polymers are amorphous and can form strong, transparent, and flexible films with tensile strengths of 89.4–100.6 MPa, Young’s moduli of 2.13–2.65 GPa, and elongations at break of 15.5–25.3%. All these polymers had low dielectric constants of 2.70–2.89 at 1 MHz and low water sorption of 0.51–0.59%.