Abstract: A self-made flame retardant containing phosphaphenanthrene and triazine-trione groups (TGD) was used to enhance the flame retardancy of polyester textiles by a back coating method, and the flame-retardant properties of resulting textiles was investigated intensively by limited oxygen index, UL 94 vertical burning experiment and cone calorimeter measurement. The results indicated that the incorporation of TGD could improve the flame-retardant properties of the textiles. When 8.1 wt % of TGD was introduced, the textiles achieved a limited oxygen index of 23.9 %, and it also exhibited a shorter burning distance and self-extinguishment in the vertical burning test. Meanwhile, the peak value of heat release rate, average effective heat of combustion, total heat release rate, and average CO2 yields of the textiles all decreased with an increase of TGD content. However, the average CO yields and total smoke release revealed a rise with increasing mass fraction of TGD. The data obtained from cone calorimeter measurement also confirmed an obvious flame-retardant effect in gas phase by using TGD. Morphology of residual char obtained from vertical burning test indicated that TGD also generated a condensed phase flame-retardant effect because of the increased char yields.

Key words: phosphaphenanthrene, flame retardant, polyester textile, coating, mechanism