Effect of Phosphorus and Bromine on Burning Rates for Cotton and a Polyester /Cotton Blend1

Abstract

Burning rate measurements have been carried out on cotton and on 50/50 polyester/cotton samples in the presence of low to moderate levels of diammonium hydrogen phosphate and/or diammonium tetrabromophthalate. The in iluence of burning mode, i.e., horizontal or top-vertical, on the rate of burning, and effects of bromine and phosphorus on oxygen sensitivity were observed.

Low levels of added retardant enhance burning rates under all conditions for horizontal burning. Similarly, oxygen sensitivity is greater for samples treated with either retardant than for untreated samples when burned in the horizontal mode. Top-vertical burning behavior of cotton resembles horizontal burning, but at slower speeds. For 50/50 polyester/ cotton, rate enhancement effects and increased oxygen sensitivity are not observed in top-vertical burning. It is specu lated that these aberrant effects may be attributable to dominance of polyester combustion at the slower burning speeds.