Chemically bonded iron carbonyl for magnetic composites based on phthalonitrile polymers

Dicarboxylic acid‐containing 1,3‐benzoxazine was synthesized and chemically bonded on iron carbonyl particles using a post‐coating method. Novel organic–inorganic hybrid magnetic composites were prepared via the interfacial reaction between magnetic phthalonitrile prepolymers and the benzoxazine functional coatings that chemically modified the iron carbonyl particles. The results showed that, compared with pure iron carbonyl particles, the modified particles could cure the phthalonitrile prepolymers efficiently and improve the interfacial compatibility of the functional composites. The magnetic composites with chemically modified particles exhibited stronger magnetism in comparison to composites containing bare particles: the saturation magnetization of the magnetic composites with equal concentration (5 wt%) of Fe(CO) 5 increased from 41.12 to 48.82 emu g −1 . Also, the magnetic composites obtained demonstrated excellent thermal stability up to 500 °C.