Synthesis of poly(imino imino ketone) (PIIK) and preparation of heat resistant PIIK foam

Poly(imino imino ketone) (PIIK) was synthesized via palladium-catalyzed C-N cross coupling reaction of 1,4-bis-(4′-bromobenzoyl) benzene and p-phenylenediamine. In view of its good thermal stability and solubility, PIIK foams with low density between 80 mg/cm3-350 mg/cm3 have been prepared via thermal induced phase separation and freeze-drying technology. The PIIK foam possessed high glass transition temperature (Tg = 193 °C) and good thermal stability with high decomposition temperature (Td = 350 °C). Furthermore, these achieved foams also exhibited excellent mechanical properties, such as high modulus and compressive strength, as well as great elongation at break (ca. 20%).