The effects of silicon and ferrocene on the char formation of modified novolac resin with high char yield

Novolac resin (NR) modified with 1, 1'-bis(dimethylsilyl) ferrocene (FeNR) was synthesized. The thermal properties and structural evolution of cured FeNR were studied to analyze the reason for high char yield of cured FeNR. Thermal stability of cured FeNR has been improved, and the char yield of cured FeNR at 800 °C can be increased by 8.82% in comparison to that of cured NR. The results show that silicon atom and ferrocene contribute to the high char yield of cured FeNR. On one hand, the Si-O structure can be kept in the system during the whole pyrolysis process, which could help to reduce the weight loss. On the other hand, introducing ferrocene into novolac resin promotes the graphitization degree and graphite crystallites of pyrolyzed resins. Moreover, the pyrolyzed products possess different magnetic properties owing to the formation of iron nanocrystal at 800 °C and Fe5Si3 nanocrystal at 1200 °C.