Interfacial coordination-assisted construction of mechanically robust, fluorescent and intumescent flame retardant epoxy resins

Conventional intumescent flame retardant epoxy resins (EP) are challenged by the weak interfacial interaction between the fillers and matrix, and particularly the introduction of desired functionality. To address this issue, herein, interfacial coordination reaction is facilely utilized to assist the construction of highly fire-safety EP with robust mechanical strength and blue-fluorescence. For demonstration, nicotinic acid-nickel chelate (NicNi) decorated ammonium polyphosphate (NicNi@APP) was strategically prepared by the in-situ growth of NicNi particles on the surface of APP. It is crucial that during the curing of epoxy system, the coordination environment of Ni2+ was gradually changed alone with the interfacial coordination reaction of DETA and NicNi@APP. Consequently, the as-cured EP was not only equipped with the blue-fluorescence possibly due to the clustering-triggered emission (CTE), but also possessed high mechanical strength. Besides, EP containing 6 wt% NicNi@APP achieved a V-0 rating under UL-94 tests, and got a limiting oxygen index (LOI) of 32.6 %. What's more, its peak of heat release rate (PHRR), total heat release (THR), total smoke production (TSP) during combustion decreased by 84.3 %, 69.8 % and 68.7 % respectively as compared to EP. Generally, this work provides a feasible strategy for the preparation of multifunctional epoxy resin with high performance.