How do phosphorus-based flame retardants interact with polyester fabric to prevent burning?

Phosphorus-based flame retardants interact with polyester fabric primarily through a chemical process that enhances the material's resistance to burning. Here's how they work:

Char Formation: When exposed to high temperatures, phosphorus-based flame retardants promote the formation of a char layer on the surface of the polyester fabric. This char layer acts as a barrier, slowing down the heat transfer to the underlying material and preventing further combustion.

Dehydration and Cross-Linking: The phosphorus compounds can cause the polyester to dehydrate and cross-link when heated. This process reduces the amount of flammable gases released during burning and increases the material's structural integrity under heat.

Dilution of Flammable Gases: Some phosphorus-based retardants release non-flammable gases (such as water vapor or nitrogen) when heated. These gases dilute the oxygen around the fabric, reducing the likelihood of the polyester catching fire.

Intumescence: In some cases, the phosphorus-based retardant causes the polyester to swell and form a foamy, protective barrier when exposed to heat. This intumescent action further insulates the fabric and protects it from the heat source.

The combination of these mechanisms makes phosphorus-based flame retardants effective in reducing the flammability of polyester fabrics, which are otherwise prone to melting and burning when exposed to fire.Using textile flame retardants can effectively reduce the flammability of fabrics, thereby enhancing their safety in the event of a fire, slowing the spread of flames, and minimizing the damage caused by fire.