The flammability and melt dripping of the widely used bio-based polyamide 11 (PA 11) have attracted much attention in the last decade, and they are still a big challenge for the fire science society. In this work, a novel single macromolecular intumescent flame retardant (AM-APP) that contains an acid source and a gas source was prepared by supramolecular reactions between melamine and p-aminobenzene sulfonic acid, followed by an ionic exchange with ammonium polyphosphate. The chemical structure of AM-APP was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. AM-APP and TiO were then introduced into PA 11 by melt compounding to improve the fire resistance of the composite. The fire performance of PA 11 composites was evaluated by the limiting oxygen index (LOI), vertical burning (UL-94), and cone calorimetry tests. The results showed that the presence of 22% AM-APP and 3% TiO increased the LOI value from 22.2 to 29.2%, upgraded the UL-94 rating from no rating to V-0, completely eliminated melt dripping, and significantly decreased the peak heat release rate from 943.4 to 177.5 kW/m. The thermal behaviors were investigated by thermogravimetric (TG) analysis and TG-FTIR. It is suggested that AM-APP produces an intumescent char structure and releases inert gases, whereas TiO may consolidate the char layers, leading to the improvement in the fire resistance of PA 11.

An eco‐friendly bio‐filler was prepared by reusing of chicken eggshell (CES), and well characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM)‐energy dispersive X‐ray spectroscopy (EDS), X‐ray fluorescence spectrometry (XRF), and thermo‐gravimetric (TG) analysis. The influence of CES on the thermal stability, flame‐retardant, and smoke suppression properties of epoxy‐based traditional intumescent system was investigated by limited oxygen index (LOI), UL 94 test, cone calorimeter test, and TG analysis. The results shows that the incorporation of CES improves the LOI value of the samples, and IFR‐3 with 37 wt% intumescent flame retardant (IFR) and 3 wt% CES exhibits the maximum LOI value of 31.5%. The results from cone calorimeter and smoke density tests reveal that the addition of CES greatly decreases the heat release and smoke production of the samples concomitant with an increase in the residual weight, which is ascribed to the formation of a more compact, thermally stable, and intumescent char against heat and mass transfer during burning. The synergistic effect on fire performance between CES and IFR depends on the content of CES, and an excessive content of CES diminishes this synergistic effect. The TG analysis shows that the intumescent system containing CES exhibits high thermal stability and char‐forming ability. Overall, CES can serve as an environmentally friendly bio‐filler and a promising synergist for intumescent systems. POLYM. COMPOS., 40:2712–2723, 2019. © 2018 Society of Plastics Engineers

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Ammonium sulfamate (AS) intercalated kaolinite (K) was successfully prepared through a three-step method, and then, it was introduced in association with intumescent flame-retardants (IFR) into polypropylene (PP). The structure of intercalated kaolinite (AS-K) was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and X-ray photoelectron spectrometry (XPS). The flammability evaluation by limit oxygen index (LOI), vertical burning test (UL-94), and cone calorimeters test (CCT) revealed that the LOI value was increased to 35.3, and UL-94 grade reached V-0 rating for the PP/IFR (23.5 wt %)/AS-K (1.5 wt %) sample; the heat release rate (HRR) value was lower than other PP composites. The thermostability analysis by TGA demonstrated that the addition of AS-K could enhance the thermal stability and the formation of char residue. It was proposed that AS-K could react with P, N, and polyaromatic rings to form a ceramic-like compact and continued to char during burning.