Synthesis and properties of novel copolymers of poly(ether ketone ether ketone ketone) and poly(ether amide amide ether ketone ketone)

A new monomer, N,N ′‐bis(4‐phenoxybenzoyl)‐ m ‐phenylenediamine (BPMPDA), was prepared via the reaction of m ‐phenylenediamine with 4‐phenoxybenzoyl chloride in N,N ‐dimethylacetamide. Novel copolymers of poly(ether ketone ether ketone ketone) and poly(ether amide amide ether ketone ketone) (PEAAEKK) were synthesized by the modified electrophilic Friedel–Crafts acylation copolycondensation of terephthaloyl chloride with a mixture of 4,4′‐diphenoxybenzophenone (DPOBPN) and BPMPDA, over a wide range of DPOBPN/BPMPDA molar ratios. The resulting copolymers were characterized by Fourier transform infrared spectroscopy, wide‐angle X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis, and so on. The results indicated that the copolymers with 10–30 mol% BPMPDA were semicrystalline and had remarkably increased glass transition temperatures ( T g s) over the conventional poly(ether ether ketone) and poly(ether ketone ketone) due to the incorporation of amide linkages in the main chains. The copolymers III and IV with 20–30 mol% BPMPDA had not only high T g s of 177–180°C, but also moderate melting temperatures ( T m s) of 324–333°C, having good potential for the melt processing. The copolymers III and IV had tensile strengths of 101.8–104.4 MPa, Young's moduli of 2.32–2.46 GPa, and elongations at break of 10.8–12.2% and exhibited high thermal stability and excellent resistance to organic solvents. POLYM. ENG. SCI., 53:2353–2359, 2013.