Melamine-containing polyphosphazene wrapped ammonium polyphosphate: A novel multifunctional organic-inorganic hybrid flame retardant

To achieve superior fire safety epoxy resins (EP), a novel multifunctional organic-inorganic hybrid, melamine-containing polyphosphazene wrapped ammonium polyphosphate ([email protected]) with rich amino groups was prepared and used as an efficient flame retardant. Thanks to the cross-linked polyphosphazene part, [email protected] exhibited high flame retardant efficiency and smoke suppression to the EP composites. Thermogravimetric analysis indicated that [email protected] significantly enhanced the thermal stability of EP composites. The obtained sample passed UL-94 V-0 rating with 10.0 wt% addition of [email protected] Notably, inclusion of incorporating [email protected] leads to significantly decrease on fire hazards of EP, for instance, bring about a 75.6% maximum decrease in peak heat release rate and 65.9% maximum reduction in total heat release, accompanied with lower smoke production rate and higher graphitized char layer. With regards to mechanical property, the glass transition temperature of EP/[email protected] was as high as 184.5 °C. In particular, the addition of [email protected] did not worsen the mechanical properties, compared to pure APP. It was confirmed that the participation of melamine-containing polyphosphazene could significantly enhance the quality of char layer and thereby resulting the higher flame retardant efficiency of [email protected]