Preparation and characterization of carbon fiber reinforced polybenzoxazine and polybenzoxazole composites from the same precursor: Use of a smart, ortho-substituted and amide-co-imide functional matrix

In the current paper, a processable, very high-performance resin matrix is used to prepare carbon fiber reinforced composites. Polybenzoxazole is a high-temperature-resistant resin and can potentially be a good matrix for fiber reinforced composite. The current paper aims at preparing a very high thermal stability composites using a smart, amide-co-imide functional polybenzoxazine that is used as the precursor to prepare a polybenzoxazole composite. According to thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA), the char yield of neat polybenzoxazine and the Tg of polybenzoxazine/CF composite are 60.5% (at 800 °C) and 190 °C, respectively. Further improvement in properties are observed for polybenzoxazole: the char yield increases to 67.5% (at 800 °C) and Tg of the polybenzoxazole/CF composite increases to 435 °C. Besides, the storage modulus keeps almost constant until 350 °C.