Hydrazinium Phosphates as Flame Retardants

Natural fibers such as cotton (cellulose) are intrinsically flammable and undergo combustion in air, once ignited. Phosphorous-containing compounds like ammonium phosphates have been investigated as flame retardants for cellulosic materials. This role of phosphates as useful flame retardants for cellulose is well known. 

Natural cellulose is a linear polymer consisting of glucopyranose units, linked by 1,4-glycosidic bonds, with several monomeric units (up to 

Monohydrazinium phosphate (MHP) and dihydrazinium phosphate (DHP) have also been investigated as flame retardants of cellulose and compared with the corresponding ammonium phosphates [6,7]. The flame retardant property of hydrazinium phosphates is checked using a Whatman No. 40 filter paper with an ash content of 0.018% as the cellulose source. This filter paper is treated with hydrazinium phosphates by dipping it into aqueous solutions of selected concentrations of 2.5% and 10% to ensure that the desired weight of phosphate is retained on the sample. The samples are then dried in air and used in pyrolysis experiments. 

The ratio of the intensity of mass 18 to 44 (water and carbon dioxide, respectively) is higher for dihydrazinium phosphate-treated cellulose than for monohydrazinium phosphate-treated cellulose or even diammonium 

Sample Peak heights of molecular ions ( i/z) Peak height ratio of mass 18 to 44 (H2O/CO2) 

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