Facile synthesis of melamine phytates and its application in rigid polyurethane foam composites targets for improving fire safety

Biomass melamine phytates (MEL-PA) flame retardant was fabricated by a facile method, and MEL-PA was used to prepare a series of RPUF/MEL-PA composites by one-step water-blown technology. Compared with that of pure RPUF, the degradation rate of RPUF/MEL-PA composites decreased at a high temperature, and the char residues increased significantly, indicating that the thermal stability of the composites is improved. The smoke density test and TG-FTIR revealed that MEL-PA can significantly inhibit the release of smoke, flammable gases (e.g. esters and hydrocarbons) and toxic and harmful gases (e.g. isocyanate compounds, aromatic compounds and CO), implying significant enhancement of the fire safety of RPUF/MEL-PA composites. SEM, Raman spectra and FTIR spectroscopy were employed to investigate char residues of the composites. MEL-PA was found to catalyse the RPUF matrix to form compact char residues with a high graphitisation degree, significantly inhibiting heat and mass transmission processes during combustion.