Synthesis and characterization of novel poly(aryl ether ketone)s containing both biphenylene and 1,4-naphthylene moieties

A monomer containing naphthalene, 4,4′-di(1-naphthoxy)benzophenone (DNOBN), was easily prepared by the condensation reaction of 4,4′-difluorobenzophenone with 1-naphthol. Novel poly(aryl ether ketone)s containing both biphenylene and 1,4-naphthylene moieties were synthesized by the electrophilic Friedel-Crafts acylation copolycondensation of isophthaloyl chloride (IPC) with a mixture of 4,4′-bis(4-phenoxybenzoyl)diphenyl (BPOBDP) and DNOBN, over a wide range of BPOBDP/ DNOBN molar ratios, in the presence of anhydrous AlCl₃ and N-methylpyrrolidone (NMP) in 1,2-dichloroethane (DCE). The copolymers with 10–30 mol% DNOBN are semicrystalline and had much higher T _gs than those of the conventional PEEK and PEKK due to the incorporation of both biphenylene and 1,4-naphthylene moieties in the main chain. The copolymers IV and V with 25–30 mol% DNOBN showed high T _gs of 182–183 °C and moderate T _ms of 336–338 °C with good potential for melt processing. The copolymers IV and V had tensile strengths of 101.2–102.5 MPa, Young’s moduli of 2.81–2.93 GPa, and elongations at break of 19.8–20.6 % and exhibited high thermal stability and excellent resistance to organic solvents.