Abstract

The prepared nano sized ammonium polyphosphates (APP) from ammonium dihydrogen phosphate and urea in the presence of ammonia solution was evaluated as flame retardant for polypropylene (PP). The results of study show that negligible change has occurred on the mechanical properties with APP addition. Both the thermogravimetric analysis (TG and DTA) and the cone calorimeter method were used for evaluation of PP/APP system. The results of TG and DTA show that the addition of APP with different percentage (1,3,5,10%) leads to decrease in the Tonset and increase in the Toutset, the calculated time of the complete degradation increases. This behavior means that the addition of different percentages of APP improve the flammability of PP. The total heat release (THR), the heat release rate(HRR), the mass loss rate (MLR), the time of ignition, the effective heat of combustion(EHC), and the smoke production and toxic gas formation were estimated from the profile of the cone calorimeter curves. From these parameters, it is observed that all the parameters decrease by adding APP to PP. From the analysis of data, it may be conclude that the addition of APP to PP improves the flammability without remarkable effect on the mechanical properties.