Synthesis and characterization of novel poly(aryl ether ketone)s containing biphenylene moieties and pendant cyano groups

Two monomers, 4,4′-bis(4-phenoxybenzoyl)diphenyl (BPOBDP) and 2,6-diphenoxybenzonitrile (DPOBN), were conveniently prepared via simple synthetic procedures from commercially readily available materials. A series of novel poly(aryl ether ketone)s containing biphenylene moieties and pendant cyano groups were synthesized by the Friedel-Crafts acylation copolycondensation of isophthaloyl chloride (IPC) with a mixture of BPOBDP and DPOBN, over a wide range of BPOBDP/DPOBN molar ratios, in the presence of anhydrous AlCl and N-methylpyrrolidone (NMP) in 1,2-dichloroethane (DCE). The copolymers with 10–50 mol% DPOBN are semicrystalline and had higher Ts than those of the conventional PEEK and PEKK due to the incorporation of biphenylene moieties and pendant cyano groups. The copolymer VI with 50 mol% DPOBN had not only high T of 168 °C, but also moderate T of 333 °C, having good potential for melt processing. The copolymer VI had tensile strength of 103.4 MPa, Young’s modulus of 2.62 GPa, and elongation at break of 20.7 % and exhibited high thermal stability and excellent resistance to organic solvents.