Flame retarding and mechanical properties of melamine phosphate-EVA compounds

Abstract

The effects of three additives in melamine phosphate group, in ethylene vinyl acetate (EVA) copolymer, on the thermal, flame-retarding, and mechanical properties were studied in comparison with those of the conventional aluminum tri hydroxide (ATH)-EVA compounds. Various amounts of melamine phosphate, melamine pyrophosphate, and melamine polyphosphate, and ATH were mixed with EVA by twin screw extruder. Tensile strength and elongation of these samples were evaluated. In addition thermal decomposition, as measured by thermogravimetric analysis, and other burning standard methods, were determined in terms of limiting oxygen index, burning rate, burning time, and the temperature at different % weight loss EVA compounds with ATH and an addition of zinc borate were also prepared. It was found that all compounds in the melamine phosphate group can exhibit flame retarding properties when adequate amounts were used (more than 30% by weight). Flame retarding properties increased, at the expense of mechanical properties, with increasing amount of additives. Synergistic effect was not observed when melamine polyphosphate was used in combination with ATH or zinc borate. Among the three melamine phosphate compounds tested, the melamine polyphosphate gave the best results.