Improvement of thermal stability and flame retardancy of polypolypropylene composite modified by ZnO and MoO3 nanowires

Herein, zinc oxide (ZnO) and molybdenum trioxide (MoO3) nanowires were prepared via the hydrothermal method. Then as-prepared ZnO and MoO3 nanowires were fabricated to form ZnO/MoO3 compound nanostructure. ZnO/MoO3 compounds were incorporated into polypropylene (PP) with various loadings by melt blending. The D-Optimal mixing design in Design-Expert software was employed to study the effects of ZnO/MoO3 compound content on flame retardancy and mechanical properties of nanocomposites. Information on performance of thermal stability and flame retardancy of PP/ZnO/MoO3 nanocomposites was obtained through thermogravimetric analysis, cone calorimeter tests, and limiting oxygen index (LOI). The results reflected that the synthesized ZnO/MoO3 compound possessed high thermal stability and flame retardancy. The addition of 15 wt % ZnO nanowires and 13 wt % MoO3 nanowires increased LOI from 18.2 to 23.0%. Meanwhile, the tensile strength of the PP/ZnO/MoO3 nanocomposite decreased by 13.8% and the elongation at break of the PP nanocomposite increased by 20.4% compared with pure PP. Response surface analysis results also indicated that the loading of ZnO/MoO3 compound had an influence on the mechanical properties and flame retardancy of PP. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48312.