Crosslinkable aromatic polyketones with maleimide pendent groups

A novel class of crosslinkable aromatic polyketones with maleimide pendent groups were synthesized by Friedel–Crafts polymerization from 5‐maleimido‐isophthaloylchloride and various aromatic reagents. The synthesized polyketones showed a poor solubility. They were characterized by inherent viscosity measurements and infrared (IR) spectroscopy. Differential thermal analysis (DTA) revealed that their crosslinking occurred at relatiively lower temperatures (167–253°C) than did thermal polymerization of ordinary bismaleimides. The thermal‐and thermooxidative stability of crosslinked resins were evaluated by dynamic thermogravimetric analysis (TGA) as well as by isothermal gravimetric analysis (IGA). They were stable in N 2 up to 303–329°C and formed anaerobic char yield 50–62% at 800–C. The thermal stability of crosslinkable polyketones was significantly increased after curing.