Chemical degradation of carbon fiber reinforced bismaleimide resin composites to recover carbon fiber and nitrogen doped carbon materials

Carbon fiber reinforced bismaleimide resin (CF/BMI) composites were recycled by chemical methods. The degradation of bismaleimide (BMI) resin was achieved in subcritical acetic acid. The C-N bonds of BMI resin were selectively cleaved by Ca(NO3)2. The results show that NO3− presents strong oxidizing ability in subcritical acetic acid and Ca2+ was beneficial to the oxidation of NO3−. The carbon fibers can be totally reclaimed from CF/BMI composites. The degradation products of BMI resin were partly carbonized due to the strong oxidation and high reaction temperature. However, the degradation products can be used to produce nitrogen doped carbon materials. The nitrogen doped carbon materials were used to catalyze the aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF). The work developed a promising strategy for the full-component recycling of waste CF/BMI composites.