A novel multi-element flame retardant containing phosphorus, nitrogen and sulfur for enhancing the fire safety of epoxy resin composites

To gain insight into more about how flame retardants containing phosphorus, sulfur, and nitrogen affect epoxy resin (EPs), a multicomponent flame retardant (Sp-ACDH) containing P/N/S was synthesized from sodium p-aminobenzene sulfonate (Sp-A), cinnamaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and applied to epoxy resin. Sp-ACDH enables the epoxy resin to achieve the desired flame retardancy. For example, with the addition of 10 wt% Sp-ACDH, the epoxy composite passed the UL-94 V-0 rating and achieved an LOI of 32.7%. Additionally, Sp-ACDH effectively slowed down EP’s ability to release heat, with EP-15 Sp-ACDH exhibiting a peak heat release rate (PHRR) that was 680 kW/m 2 rather than pure EP’s 1204.4 kW/m 2 . Eventually, the samples were characterized using Scanning electron microscopy (SEM), Raman spectroscopy, and Thermogravimetric analysis-fourier transform infrared spectroscopy (TG-FTIR) spectra, and the samples were analyzed, it revealed that Sp-ACDH’s flame-retardant properties were active in both the gas and condensed phases.