One-spot synthesis of a benzene-rich triazine-based hyperbranched charring agent and its efficient intumescent flame retardant performance for thermoplastic polyester elastomer

•A highly effective hyperbranched charring agent (CDS) based on triazine and rich in benzene was synthesized.•The intumscent flame retardant composed of CDS and AlPi can effectively flame retard TPEE and inhibit its droplets.•Deep research has been done on the TPEE/AlPi/CDS condensed phase flame retardant mechanism. An intumescent flame retardant (IFR) system was created using a benzene-rich triazine-based hyperbranched charring agent (CDS) and aluminum diethlyphosphinate (AlPi) to enhance the flame resistance of thermoplastic polyester elastomers (TPEE). Thermogravimetric analysis (TGA) results revealed that CDS had substantial char residue (50.8 wt%) and good thermal stability at 700 °C. The limiting oxygen index (LOI) value achieved 30.2% and it passed the V-0 rating in vertical combustion (UL-94) with the integration of 20 wt% (wt%) IFR (AlPi:CDS = 3:1) into TPEE matrix. Scanning electron microscope (SEM), laser Raman spectroscopy (LRS), and heating infrared spectroscopy were used to examine the morphology and chemical makeup of char residues, as well as the evolution of the structure during the heating process. The outcomes demonstrated the compatibility of CDS and AlPi in both the gas phase and the condensed phase. After burning, the high-efficiency flame-retardant TPEE composite created a dense, continuous char layer that contained triazine rings and aromatic ring structures.