Facile fabrication of biobased P N C-containing nano-layered hybrid: Preparation, growth mechanism and its efficient fire retardancy in epoxy

A bio-based organic-inorganic hyperbranched hybrid (PAMA), possessing unique nano-layered structure, was designed and prepared by the neutralization reaction between phytic acid and melamine, then used as a multi-function intumescent flame retardant for epoxy resin (EP). FTIR, 1H NMR, XRD, XPS, TGA and DSC were employed to investigate the chemical structure, growth mechanism and thermal behaviour of PAMA. SEM and TEM results confirmed the nano-layered structure of the PAMA. The limiting oxygen index (LOI) of EP incorporated with 6 wt% PAMA (EP-6) was 29.7%, and the UL-94 V-0 rating was also achieved. In contrast to the EP, the peak heat release rate (PHRR), total smoke production (TSP), and fire growth rate (FIGRA) of EP-6 were reduced by 62.3, 36.2, and 62.16%, respectively. The flame retardant mechanism of PAMA was further depicted using TG-FTIR and SEM/EDX techniques. In addition, the mechanical properties of EP composites are reinforced by the incorporation of PAMA. All the results demonstrate that the nano-layered PAMA is a high-efficient and eco-friendly fire retardant for EP.