Combustion behaviors of cotton fabrics treated by a novel nitrogen- and phosphorus-containing polysiloxane flame retardant

A novel flame-retardant agent, nitrogen- and phosphorus-containing polysiloxane [(IB-co-N-MDPA)PDMS] was synthesized, and it was employed on cotton fabrics. Cone calorimeter testing showed that the treated cotton fabric with (IB-co-N-MDPA)PDMS became less flammable with longer time to ignition and lower value of HRR, THR, EHC and mass loss. Thermogravimetric analysis demonstrated that (IB-co-N-MDPA)PDMS improved the thermal and thermo-oxidative stability of cotton fabric with fewer flammable volatiles, and more char is produced during combustion. Scanning electron microscopy showed that the surface of treated cotton fabric after combustion was covered by a compact char layer which indicated that (IB-co-N-MDPA)PDMS favored the formation of char as evidenced by the FTIR of residues. Furthermore, EDS analysis results demonstrated that the concurrent presence of Si and P in flame retardant effectively enhance the flame retardancy of cotton fabric with the remarkable amount of Si and P elements that were still present on the surface of fibers after combustion.