Phosphorus Flame Retardants

Phosphorus FR additive benefits: 

 Can be both vapor phase and condensed phase flame retardants.

 Can be very effective at lowering heat release rate at low loadings of additive. 

Phosphorus FR additive drawbacks: 

 Tend to generate more smoke and carbon monoxide during burning. 

 Not effective in all polymers.

 Starting to be under regulatory scrutiny. 

Newer technology (1950s). A mature technology but lots of other possible chemical structures to explore and use for flame retardancy.