| Polyurethane materials are widely used in construction, automobiles, home appliances and other fields because of their excellent mechanical properties, chemical resistance and insulating properties. However, polyurethane materials are easily combustible and release a large amount of toxic gases during combustion, posing a serious threat to personal safety and the environment. In this paper, polyurethane elastomers were prepared from poly(propylene glycol), tolyl-2,4-diisocyanate blocked (PPGTD), isophorone diisocyanate (IPDI) and isophorone diamine (IPDA) by solution method. PU/FR composites with excellent thermal stability, flame retardancy and mechanical properties were prepared by adding aluminium diethylphosphonate (ADP), aluminium hypophosphite (AHP) and piperazine pyrophosphate (PAPP) to the polyurethane matrix, respectively. The thermogravimetric (TGA) test results showed that compared with pure PU, the PU/ADP 25 and PU/AHP 25 composites showed improved thermal stability with increased T5 wt%, Tmax and residual carbon, decreased maximum thermal weight loss rate. The results of cone calorimetry (CONE) experiments showed that the pHRR values of PU/ADP 25, PU/AHP 25 and PU/PAPP 25 were reduced by 58.8%, 73.5% and 77.5%, and the THR values were reduced by 38.6%, 45.8% and 49.7%, respectively. Thermogravimetric infrared coupling (TG-IR) and laser Raman spectroscopy were used to further investigate the flame retardant mechanism of the materials, and the results showed that the incorporation of ADP, AHP, and PAPP significantly reduced the generation of carbon monoxide, carbon dioxide, and alkane compounds gas-phase products in the samples of PU/ADP, PU/AHP, and PU/PAPP, and meanwhile, the densification and continuity of residual carbon were significantly improved, which can provide more valuable time for fire The residual charcoal density and continuity were significantly improved, which won more precious time for fire rescue. |
