Novel fire‐resistable PUF/APP/Gelatin composites from wasted PET bottles: Synthesis and processing

Novel polyurethane (PUF)/ammonium polyphosphate (APP)/gelatin (GEL) composites were fabricated by utilizing an oligodiol synthesized via the glycolysis of waste poly(ethylene terephthalate) and incorporating with APP/GEL, achieved through both coating and mixing methods. Fourier‐transform infrared spectroscopy and 1 H‐nuclear magnetic resonance results confirmed the chemical structure of the oligodiol. The density of the PUF reduced from 71 to 63 g/dm 3 by mixing APP/GEL, which are suitable for lightweight applications. The flame retardancy of the PUF matrix was significantly enhanced under the presence of APP/GEL, achieving a UL‐94 rating of HB at 10 wt% loading and V‐0 at 20 wt% loading. Thermogravimetric analysis revealed a notable increase in char residue, confirming the condensed phase mechanism of APP/GEL within the PUF matrix.