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. [ABSTRACT FROM AUTHOR]