Preparation of a novel flame retardant containing triazine groups and its applications on cotton fabrics

In order to improve the flame retardancy of cotton fabrics and reduce its fire risk, a novel triazine-based flame retardant, (3-((6-((4,6-dichloro-1,3,5-triazin-2-yl)amino) hexyl) amino)-3-oxopropyl) (phenyl) phosphinic acid (CPHDT), was successfully synthesized with 3-Hydroxyphenylphosphinyl-propanoic acid and 1,6-Diaminohexane and Cyanuric chloride. The structures of (3-((6-aminohexyl) amino)-3-oxopropyl) (phenyl) phosphinic acid (intermediate I), CPHDT, and CPHDT-treated cotton fabrics at different heating temperatures were measured by Fourier transform infrared spectroscopy (FTIR). The flame retardancy of CPHDT-treated cotton fabrics were studied by limiting oxygen index (LOI) and vertical flammability test. The results showed that the limiting oxygen index of cotton fabrics treated by 400 g/L CPHDT was 28.4%, which was 10.4% higher than that of pure cotton fabrics. Vertical flammability test demonstrated that the after-glow time and after-flame time of CPHDT-treated cotton fabrics was immensely shortened compared with pure cotton fabrics. The thermogravimetric (TG) analysis and scanning electron microscopy (SEM) showed that the cotton fabrics treated with CPHDT exhibited good thermal stability and char-forming ability compared to pure cotton fabrics. These results indicated that CPHDT increased flame retardancy of cotton fabrics by inhibiting formation of levoglucosan in cotton fibers during combustion.