Metal‐organic frameworks derived ZnO@MOF@PZS flame retardant for reducing fire hazards of polyurea nanocomposites

Transition metal as flame retardant has attracted intense interests in recent years. In this work, ZnO@MOF@PZS was prepared via hydrothermal and polycondensation methods. ZnO nanoflowers played the role as a template for growth of MOF@PZS and zinc source for formation of MOF. Subsequently, the obtained ZnO@MOF@PZS was mixed into polyurea (PUA) to investigate its flame retardancy and toxicity suppression properties. The cone calorimeter test (CCT) showed that ZnO@MOF@PZS significantly improved the flame retardancy of PUA composites. The addition of 3 wt% ZnO@MOF@PZS into PUA could result in peak heat release rate (PHRR), total heat release (THR) and total CO production (TCO) of 28.30%, 19.59% and 36.65%, respectively. The result of universal testing machine showed that ZnO@MOF@PZS‐add PUA had better mechanical properties. It is notable that the improved flame retardant properties for PUA composites are mainly attributed to ZnO@MOF@PZS promoting the formation of dense char residue.