Synthesis and Characterization of Copolymers of Poly(aryl ether ketone amide) and Poly(aryl ether ketone ketone)

A new monomer containing amide linkages, N, N′-bis(4-phenoxybenzoyl)- p-phenylenediamine (BPBPPD), was prepared by condensation of p-phenylenediamine with 4-phenoxybenzoyl chloride in N, N-dimethylacetamide (DMAc). A series of novel copolymers of poly(ether ketone amide) (PEKA) and poly(ether ketone ketone) (PEKK) were synthesized by electrophilic Friedel—Crafts solution copolycondensation of isophthaloyl chloride (IPC) with a mixture of BPBPPD and diphenyl ether (DPE), over a wide range of BPBPPD/DPE molar ratios, in the presence of anhydrous aluminum chloride and N-methylpyrrolidone (NMP) in 1,2-dichloroethane (DCE). The polymers obtained were characterized by different physico-chemical techniques. The crystallinity, melting temperatures, and glass transition temperatures of the polymers increased with increase in the BPBPPD content in the reaction system due to the existence of hydrogen bonding in the polymer, the copolymers with 50—90 mol% BPBPPD were semicrystalline. The copolymers with 50—60 mol% BPBPPD had high T g values of 185—191 °C, moderate Tm values of 341—348 °C, tensile strengths of 102.4—104.6 MPa, Young’s moduli of 2.53—2.68 GPa, and elongations at break of 11—13%. The copolymers exhibited high thermal stability and good resistance to common organic solvents.