Red phosphorus–controlled decomposition for fire retardant PA 66

Abstract

ABSTRACT:The thermal degradation and the combustion behavior of glass fiberreinforced PA 66 materials containing red phosphorus were investigated. Thermogravimetry (TG), TG coupled with FTIR, and TG coupled with mass spectroscopy were used to investigate the thermal decomposition. The flame retardant red phosphorus was investigated with respect to the decomposition kinetics and the release of volatile products. The combustion behavior was characterized using a cone calorimeter. Fire risks and fire hazards were monitored versus external heat fluxes between 30 and 75 kW/m 2 . Red phosphorus acts in the solid phase and its efficiency depends on the external heat flux. The use of red phosphorus results in an increased amount of residue and in a corresponding decrease in total heat release. The decrease of the mass loss rate peak results in a corresponding decrease of the peak heat release. With increasing external heat flux applied the first effect on the total heat release decreases linearly, whereas the second effect on the peak heat release expands linearly. The investigation provides insight into the mechanisms of how the fire retardant PA 66 is achieved by red phosphorus controlling the degradation kinetics. Taking into account that a decrease of the volatile products also leads to a decrease of heat production in the flame zone and that the char acts as heat transfer barrier, a reduced pyrolysis temperature is suggested as a further feedback effect.

Fire risks of burning asphalt

“…reported for filled systems that show the formation of a less effective protection layer at the surface, as have been reported for some microcomposites and glass fibre reinforced non-charring materials [4][5][6]. We propose that this similarity is not a coincidence, but, together with the appearance of the residue (Figure 3), quite reasonably indicates the difference between the materials.…”

Phosphorus‐Containing Polysulfones

“…However, it was shown that the mechanisms and their efficiency depend on such factors as the chemical structure of the phosphorus-containing compounds, their interactions with the matrix or additional additives, the water content and the pH value during decomposition [117][118][119][120]. Indeed, the understanding of mechanisms and their controlling interactions is as yet limited.…”

Effects of interfacial modification on the thermal, mechanical, and fire properties of high‐impact polystyrene/microencapsulated red phosphorous

“…[2][3][4][5][6][7] The flame retardancy of RP in polymers can act in both the condensed phase and the gas phase. 3,[8][9][10][11] Condensed phase mechanisms of RP increase char formation, which decreases the combustible volatiles and therefore the total fuel support of the flame. Furthermore, the char can act as a barrier, decreasing the mass loss rate.…”