Magnesium hydroxide/graphene oxide chip in flakes structure and its fire-retardant reinforcement of polypropylene

In the contribution, magnesium hydroxides and graphene oxide were synergistically combined to prepare the chip-in-flakes nanohybrid (Mg(OH) 2 /GO, MGO) via one-step hydrothermal approach for improving fire retardancy of polypropylene. Various characterizations confirmed its composition, structure and morphology. The fire-retardant evaluations illustrated that limiting oxygen index (LOI) of PP composite with 50 wt.% MGO was improved to 27.8% with UL-94 V-0 rating compared with virgin PP (17.4%, no rating). In parallel, the peak heat release rate, total heat release and smoke production rate of PP/MGO (PMG) were reduced by 80.5%, 30.8% and 79.4% respectively. The mechanism investigation uncovered that the conspicuous fire retardancy and smoke suppression were credited to the synergistic effect between GO and Mg(OH) 2 toward the optimized physical barrier. Furthermore, dynamic mechanical analysis (DMA) disclosed the highest modulus (8043 MPa) at -71 °C relative to 3236 MPa of pure PP. In viewpoint, hierarchical nano-flakes with synergistic effect offered an effective approach for the fire-safe polymer.