The effect of strawberry-like nickel-decorated flame retardant for enhancing the fire safety and smoke suppression of epoxy resin

Abstract

Organic-inorganic hybrid materials have received widespread attention because they combine the excellent characteristics of organic polymers and inorganic materials. In this work, a nanohybrid flame retardant PZS@PDA@Ni(OH)2 with strawberry-like architecture is prepared via the coating of biomimetic polydopamine (PDA) on polyphosphazene microspheres (PZS), followed by the self-assembly of Ni(OH)2. The effects of PZS@PDA@Ni(OH)2 on combustion behavior and smoke release of epoxy resin (EP) are characterized by cone calorimetry test (CCT), Thermogravimetric analysis-infrared spectrometry (TG-IR) and Raman tests. The results show that EP composites with 5 wt% PZS@PDA@Ni(OH)2 give rise to 69.8% reduction in peak heat release rate (pk-HRR) and possess the limiting oxygen index (LOI) of 31.8%, achieving UL-94 V-0 rating. Besides, owing to the synergistic effect of phosphorus-nitrogen and catalytic charring effect of Ni(OH)2 nanoparticles, the char residual of EP composites exhibits compact and dense structure, which is responsible for the remarkable flame retardancy. Meanwhile, Ni(OH)2 nanoparticles play a catalytic role in conversion of flammable gases, and the carbon monoxide production (COP) of EP composites with 5 wt% PZS@PDA@Ni(OH)2 is reduced by 58.3%. As a highly efficient flame retardant, PZS@PDA@Ni(OH)2 has promising potential in reducing the fire hazards of EP composites.