The impact of DOPO‐derived phosphoramides containing triazine moieties on the flame retardancy and smoke suppression properties of waterborne polyurethane

Abstract

AbstractWaterborne polyurethane (WPU), which is a novel and environmentally friendly variety of polyurethane, replaces organic solvents with water. It has been extensively utilized in diverse fields encompassing coatings, textile finishing, building decoration, adhesives, plastic chemistry, and others. However, WPU is inherently flammable and releases a significant amount of smoke production during the combustion process. This research presents an original fire‐resistant Waterborne Polyurethane (WPU) with a newly‐integrated flame‐retardant component comprising a triazine phosphoramidate segment derived from 9,10‐dihydro‐9‐oxo‐10‐phosphaphenanthrene‐10‐oxide (DOPO) within its primary structure. In comparison to pure WPU, the limiting oxygen index (LOI) of flame‐retardant WPU (FRWPU) increased from 19.6% to 29.2%. In UL‐94 testing, the FRWPU film achieved a V‐0 rating with only 6% retarding component. Additionally, in cone calorimetry tests, Total Heat Release (THR), peak Heat Release Rate (pHRR), Total Smoke Production (TSP), Smoke Production Rate (SPR), and peak Carbon Monoxide Production Rate (pCOP) are decreased by 27.7%, 16.2%, 64.6%, 61.3%, and 77.8%, respectively. The greater degree of graphitization observed in the residual carbon substantially impeded heat exchange and the emission of smoke during combustion. Flame‐retardant intermediate segments greatly improved the FRWPUs' ability to suppress smoke and remain flame‐retardant. The creation and formulation of aqueous polyurethanes that are flame‐retardant can benefit greatly from the insights and references offered by this research.