A novel halogen-free phosphorus-nitrogen-silicon flame retardant monomer with reactive siloxy groups

N

-(diphenylphosphino)-1

1-diphenyl-

N

-(3-(triethoxysilyl)propyl) phosphinamine (DPTA) has been synthesized and was applied to the fire-resistant finishing of cotton fabrics. The molecular structure of DPTA has been well characterized by elemental analysis

FTIR

1

H NMR

and

31

P NMR spectroscopies. The chemically-grafted cotton fabrics

which were treated with 25 wt% DPTA

were obtained and confirmed by attenuated total reflectance Fourier infrared spectroscopy (ATR-FTIR). The flame retardancy and thermal property of the treated samples were investigated by limited oxygen index (LOI)

vertical flammability test (VFT)

thermogravimetric analysis (TGA) and microscale combustion calorimeter (MCC). It is noted that in vertical flammability test

the treated samples extinguished immediately upon removing the ignition source

whereas the untreated one was completely burned out. Furthermore

TGA and MCC tests revealed that the treated samples produced a high char formation and a low heated release during combustion. The surface morphology

of the untreated and treated samples and the char residues after LOI tests were observed by scanning electron microscopy (SEM). Therefore

all the results showed that the treated cotton fabrics with 25 wt% DPTA apparently improved the fireresistant and thermal performances.