Synergistic Flame Retardancy of MXene and Poly(p-Phenylene Oxide) on High-Performance Recycling Waste Rubber Modified Polystyrene Composites

Abstract

The development of high-performance polystyrene composites modified with recycling waste tire rubbers composed of natural and synthetic rubber mixture is highly desirable for a sustainable society. To tackle the intrinsic fire issue of waste tire rubber and polystyrene (WTRPS) composites for its advanced applications, the synergistic effect of fire additives MXene and poly(p-phenylene oxide) PPO on the performance of WTRPS composites was investigated in this work. The limited oxygen index values of WTRPS composites with MXene and PPO loading at 15 and 40 wt% were  increased to 23.0%, compared to that of WTRPS at 17.0%. Additionally, the heat release rate, total heat release, and peak of heat release rate of resulting composites showed obvious decreases, confirming their synergistic fire retardancy effects on WTRPS composites. The synergistic mechanism was based on the char effect of PPO, heat sink effect of MXene, and catalyst effect of titanium dioxide generated from MXene. The synergistic strategy in this work paves a new avenue to develop fire retarding bio-composites of wood flour reinforced polyhydroxyalkanoates along with environmentally friendly fire additives (e.g., MXene and lignin or phytic acid) for advanced applications.