Phosphorus flammability

PHOSPHORUS WHITE Yellow phosphorus Flammable Solid, I 3 3 t ... 

Phosphorus Flammable or combustible high environmental hazard 87.04 ... 

Chromic(VI) acid Acetic acid, acetic anhydride, acetone, alcohols, alkali metals, ammonia, dimethylformamide, camphor, glycerol, hydrogen sulflde, phosphorus, pyridine, selenium, sulfur, turpentine, flammable liquids in general... 

Red Phosphorus. This aHotropic form of phosphoms is relatively nontoxic and, unlike white phosphoms, is not spontaneously flammable. Red phosphoms is, however, easily ignited. It is a polymeric form of phosphoms having thermal stabiUty up to ca 450°C. In finely divided form it has been found to be a powerful flame-retardant additive (26,45—47). In Europe, it has found commercial use ia molded nylon electrical parts ia a coated and stabilized form. Handling hazards and color have deterred broad usage. The development of a series of masterbatches by Albright Wilson should facihtate further use. 

Phosphides are binary compounds containing anionic phosphorus (P ). Heavy metal, alkali, and alkaline earth metal phosphides exist but few of them are commercially important. Phosphides hydrolyze to the flammable and toxic gas phosphine (PH3). The hydrolysis reaction of aluminum phosphide is given below ... 

ORGANIC PHOSPHORUS COMPOUND, MIXED WITH COMPRESSED GAS ORGANOCHLORINE PESTICIDES, FLAMMABLE, LIQUID, TOXIC, n.o.s.,... 

Fire Hazards - Flash Point (deg. F) 82 - 105 CC (solutions only pure liquid difficult to burn) Flammable Limits in Air (%) Not pertinent Fire Extinguishing Agents (for solutions) Foam, dry chemical, or carbon dioxide Fire Extinguishing Agents Not to be Used Water may be ineffective Special Hazards of Combustion Products Oxides of sulfur and phosphorus are generated in fires Behavior in Fire Not pertinent Igrution Temperature Not pertinent Electrical Hazard Data not available Burning Rate (for solutions) 4 mm/min. 

Few industrial uses have so far been found for phosphides. Ferrophosphorus is produced on a large scale as a byproduct of P4 manufacture, and its uses have been noted (p. 480). Phosphorus is also much used as an alloying element in iron and steel, and for improving the workability of Cu. Group 3 monophosphides are valuable semiconductors (p. 255) and Ca3P2 is an important ingredient in some navy sea-flares since its reaction with water releases spontaneously flammable... 

Reduction in flammability is achieved by the incorporation of flame retardants into the polymer. Two possible approaches to this are available either the use of additives blended into the polymer at processing stage (additive type) or the use of alternative monomers which confer reduced flammability on the final product (reactive type). A number of elements have been found to assist with conferring flame retardancy on polymers, the main ones being bromine, chlorine, nitrogen, and phosphorus. 

A comparison of bromine and phosphorus compounds on the flammability of PET fiber shows phosphorus (as phosphine oxide) to be 3.7 times more effective than bromine (Table 1). No synergy was observed. Nevertheless, phosphorus was shown to be more effective than antimony normally used as a synergist, resulting in a higher oxygen index at a lower concentration (Table 2). 

Polyphosphazenes are intrinsically fire-resistant materials because of the presence of phosphorus and nitrogen in the polymeric chain. A low flammability is thus one of the most important properties of polyphosphazenes, particularly of the polyaryloxyphosphazenes I, in which R may be H, halogens, and alkyl or alkoxy groups. 

Use of a free flame instead of a heating bath to distil acetyl chloride produced from acetic acid and phosphorus trichloride caused the residual phosphonic ( phosphorous ) acid to decompose violently to give spontaneously flammable phosphine... 

Potassium nitride Mellor, 1940, Vol. 8, 99 Potassium and other alkali-metal nitrides react on heating with phosphorus to give a highly flammable mixture which evolves ammonia and phosphine with water. 

However, PH3 is not the only hydride of phosphorus, and it is not the only product of this reaction. The other hydride of phosphorus is diphosphine, P2H4, which is produced in the reaction just shown. This compound is spontaneously flammable in air, and it ignites phosphine, which is also flammable. 

PMMA - Red Phosphorus System. The initial reaction that was investigated was that between PMMA and red phosphorus (4-51. Phosphorus was chosen since this material is known to function as a flame retardant for oxygen-containing polymers (1 2). Two previous investigations of the reaction of PMMA with red phosphorus have been carried out and the results are conflicting. Raley has reported that the addition of organic halides and red phosphorus to PMMA caused moderate to severe deterioration in flammability characteristics. Other authors have reported that the addition of chlorine and phosphorus compounds are effective flame retardant additives (12). 

Carnahan, J. C. Haaf, W. Nelson, G. Lee, G. Abolins, V. Shank, P. Investigations into the Mechanism for Phosphorus Flame Retardancv in Engineering Plastics. Proceedings of the 4th International Conference on Flammability and Safety, San Francisco, 1979. 

Flammability of Phosphorus-Containing Aromatic Polyesters A Comparison of Additives and Comonomer Flame Retardants... 

Preparation of Samples for Flammability Testing. Samples of the phosphorus containing terepolymers and of the polymer blends were converted to film by compression molding on a Carver Laboratory Press with electrically heated platens. The films were prepared at 250°C and 20,000 lb. pressure, using a 10 mil thick frame mold. Samples (2" x 1/4") were cut from this film for flammability testing. 

Sample Uniformity. It is apparent that the phosphorus atoms in both the copolymer and blend systems are all in the same environment, i.e. bonded to resorcinol moieties. In addition, since all of the phosphorus is in the form of polymeric species, differences in flammability due to volatility can be eliminated from consideration. 

Thermal gravimetric analysis shows that the increase in phosphorus content results in char yield increases which are correlatable with the self-extinguishment time decreases. This led to the conclusion of phosphorus "rich" barrier shielding the surfaces as a mechanism of the flammability decrease. 

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