Combination effect of zirconium phosphate nanosheet and PU-coated carbon fiber on flame retardancy and thermal behavior of PA46/PPO alloy

How to effectively enhance the flame retardancy of polyamide 46/polyphenylene oxide (PA46/PPO) alloy is one of the key issues needed to be addressed. In this work, organic-modified zirconium phosphate (OZrP) nanosheet was incorporated with PU-coated carbon fiber (CF) to flame-retard PA46/PPO alloy. The combination of OZrP and CF showed an outstanding combination effect in improving the flame retardancy and thermal stability of PA46/PPO. With the incorporation of 2 wt% OZrP and 20 wt% CF, the peak heat release rate and peak smoke production rate of PA46/PPO were reduced by 65.6% and 86.2%, respectively. Besides, the T i (temperature at 5% weight loss) and the residue of PA46/PPO/OZrP/CF were increased by 13.2 °C and 20.9 wt%, respectively, compared with PA46/PPO. The flame-retardant mechanism was further studied and revealed: when being burned, CF acted as the skeleton to improve the strength of char; simultaneously, OZrP catalyzed the carbonization of the polymer chains on the CF surface to form a strong and compact protective char layer, which blocked the transmission of heat and combustible gases, thus effectively improved the flame retardancy of the composite.