Synthesis and properties of halogen-free flame retardant thermoplastic polyurethane elastomers based on Fyrol-6

A series of segmented flame-retardant thermoplastic polyurethane elastomers (FTPUEs) was synthesized. Structural characteristics, thermal stability, mechanical properties, and flame retardancy were systematically characterized using Fourier transform infrared spectroscopy (FTIR), tensile testing, limiting oxygen index (LOI), and cone calorimetry. Key findings reveal that optimal mechanical performance was achieved at 8 wt% Fyrol-6 loading, exhibiting a peak tensile strength of 8.6 MPa coupled with 780% elongation at break. Conversely, enhanced flame resistance emerged at 15 wt% Fyrol-6 content, where the LOI value rose to 24.7% and total heat release declined to 29.8 MJ/m2. These results demonstrate that incorporating Fyrol-6 simultaneously improves flame suppression and ductility in FTPUEs.