In this paper, we introduce three high-performance polymers with similar structures, poly(imino ether ketone) (PIEK)s, which are synthesized by the ligand free copper-catalyzed C-N cross coupling reaction of aryl halides and primary aromatic diamines at moderate temperature. The influence of the solvents, base, temperature, and catalyst ligands on the polycondensation reaction is investigated. The structures of the polymers are characterized by means of 1H NMR spectroscopy, FTIR spectrometer and elemental analyses, and the results show a good agreement with the proposed structure. They all exhibit high glass transition temperature (Tg>170 oC), good thermal stability with high decomposition temperature (Td,5%>440 oC), and an excellent solubility in most organic solvents. In view of its good thermal stability and solubility, PIEK-1 foam with low density, 96 mg/cm3, is prepared via thermal induced phase separation and freeze-drying technology. The PIEK-1 foam possesses higher thermal stability than that of basal PIEK-1 (Td,5%>465 oC). Furthermore, due to intermolecular hydrogen bonds of the polymers, the achieved foam exhibits good mechanical property.
