Flame retardancy of pet textile treated by flame-retardant waterborne polyurethane with phosphorus-nitrogen effects

A flame retardant waterborne polyurethane (PU) was prepared by synthesizing reaction of N, N-bis(2-hydroxymethyl) aminoethyl phosphonic acid dimethyl ester and toluene diisocynate. Then it was smeared on the poly(ethylene terephthalate) (PET) fabric, and the performance of flame retardant, resistance to launder, and thermo-gravimetric of the PU treated fabric were investigated. The residue carbon layer after combustion was characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) as well. The results show that the LOI value of the PU treated flame-resistant fabric is enhanced 5.7% compared with that of the base fabric, and the vertical combustibility could achieve GB/T5455-1997 B1 level. The cloth surface is clean after combustion and has good resistance to launder. After combustion, fabric surface forms integrate and smooth carbon layer without holes. The content of P in residue carbon is far more than that in the original flame-resistant fabric, and the P enriched in residue carbon has strong ability of flame retardant. The fast thermal decomposition stage of the PU treated fabric is shortened and the maximum decomposition speed is reduced 32.7% in the TG curve of the PU treated flame-resistant fabric.