Flame resistance of cotton fabric finishing with N-hydroxymethylacrylamide spirophosphate

In this work, spiro-phosphorus oxychloride (SPDPC) was synthesized through pentaerythritol and phosphorus oxychloride, which was reacted with N-methylol acrylamide (NMA) as an intermediate to synthesize a novel phosphate-based flame retardant N-methylolacrylamide spiro cyclic phosphate (SPMA). The structure of SPMA was characterized using Fourier transform infrared, nuclear magnetic resonance. In order to further improve flame retardant properties of SPMA, it was compounded with different proportions of ammonium polyphosphate (APP) to better flame retardant of cotton fabrics. The combustion properties and mechanical properties of flame retardant cotton fabric with SPMA/APP were tested. The results showed that flame retardancy of flame retardant cotton fabric was significantly increased by increasing the APP. The char surface morphology of flame retardant cotton fabrics after cone calorimeter combustion was tested by scanning electron microscopy. It is shown that the char surface was smooth which proves that SPMA compounded with APP formed a stable network and increased the thermal stability of flame retardant cotton. Graphical abstract The combination of SPMA and APP was finished on cotton fabric through UV cross-linking, which presented an obvious flame retardant effect for cotton fabric.