THERMAL-DECOMPOSITION BEHAVIOR OF MELAMIN E CYANURATE

The thermal decomposition were studied for melamine cyanurate which wa s a very effective fire retardant for polyamide resins. The hydrogen b ond distances increase with an increase in temperature. Some intermole cular hydrogen bond bridges of melamine cyanurate are broken at a temp erature near 360 degrees C. At this temperature, melamine cyanurate do not always yield corresponding equimolar amounts of melamine and cyan uric acid. The pyrolysis of melamine cyanurate led to the formation of volatile or sublimate compounds such as ammonia, water, carbon dioxid e, cyanic acid, melamine, and cyanuric acid. The resulting ammonium cy anate is due to the gas-phase reaction between ammonia and cyanic acid , and the deposited melamine cyanurate is also due to the gas-phase re action between melamine and cyanuric acid sublimed. On the other hand, the residual melamine cyanurate condensed in the temperature range of 420 to 450 degrees C, and transformed to an material above 450 degree s C. The implications of thermal decomposition behavior for melamine c yanurate were discussed based on crystal structure and thermal decompo sition products.