Ammoniumphosphate—Decabromobiphenyl oxide synergistic effect in treatment of polyester/cotton blend

Abstract

Polyesteri'cotton blend (87.5: 12.5%) was treated with various concentrations of diammonium hydrogen phosphate (DAP)-Decabromobiphenyl oxide (DBBO) mixture. The flammability of the resulting systems was determined by the limiting oxygen index (LOI) and simultaneous thermal analysis (TA) methods. Evaluation of the results was achieved by plotting the variation of the LO1 with the percentage of ammonium phosphateDBB0 mixtures at constant total additive loadings on triangular diagrams. The activity of the inorganic salt as a flame retardant was found to be synergistically enhanced by the addition of the DBBO. The maximum interaction between the two additives occurred at bromine-phosphorus atomic ratio of about 3: 1. This corresponds to the stoichiometric ratio for the formation of phosphorus tribromide, PBr,, a species which most probably interacts with the acidic products resulting from the thermal decomposition of the polyester and thus changes their nature so that they become no longer capable of recombination with the other decomposition fragments to produce flammable gases.