Quantitatively Measuring the Gas Phase and Condensed Phase Flame Retardant Efficiency (PPT)

摘要

Microscale combustion calorimetry (MCC) can be run with nitrogen environment and nitrogen/oxygen mixture environment. In both of the environments, the decomposed species will be completely oxidized. Therefore, no gas phase FR activity will be revealed. However, in the condensed phase, when the test is conducted under the nitrogen environment, which simulates the real fire scenario that solid polymer would undergo anaerobic decomposition, it should preserve any char that a sample can generate. Nevertheless, when the test is conducted in nitrogen/oxygen mixture environment, since there is enough oxygen supply and the temperature of the pyrolysis chamber continuously increases, even the char will be decomposed, i.e. energy that had been preserved in char is released in this case. Therefore, the difference in total heat release (THR) measured in the two environments should provide an indication of condensed phase flame, retardant efficiency. Similarly, since materials in both Cone calorimetry and MCC (nitrogen) undergo similar anaerobic decomposition condition, the difference between the two test methods is in the combustion process (incomplete, if any, in Cone and complete oxidation in MCC), therefore, the gas phase FR efficiency can be estimated.