Investigation of UiO-66 as Flame Retardant and Its Application in Improving Fire Safety of Polystyrene

Dense smoke released during the combustion of polystyrene (PS) potentially limits its applications in some fields. In this study, a Zr-based metal-organic framework (UiO-66) was prepared via the solvothermal method and added to PS to suppress its smoke emission. Well-defined UiO-66 particles showed an excellent dispersion state and good compatibility in the PS matrix. The introduction of UiO-66 improved the flame retardancy and smoke suppression of PS. The peak heat-release rate and total heat release were reduced by 26.8% and 14.7%, respectively, for PS/ UiO-66-5 wt%. Moreover, the smoke emissions of PS composites were evidently suppressed, and more than a 35% reduction in total smoke production was obtained with 5-wt% UiO-66. Through the analysis of the residues and pyrolysis products of PS composites, the mechanisms of enhanced flame retardancy and smoke suppression can being speculated as the promoted char-forming and heat barrier of UiO-66. This work offers a significant reference for the further study of UiO-66 and polymer materials.