Abstract: The explosive characteristics of polypropylene (PP) dust and the restraining effect of melamine polyphosphates (MPP) on polypropylene dust explosion were studied by using a 20 L spherical explosive device. The results show that the explosive strength of polypropylene dust with the mass concentration of 300 g/m3 is the highest, the maximum explosive pressure is 0.746 MPa, the maximum explosive pressure rising rate is 60.508 MPa/s, and the maximum explosive index is 16.398 MPa·m/s. With the increase of the mass fraction of MPP powder, the maximum explosion pressure, the rate of increase of the maximum explosion pressure and the explosion index of polypropylene dust decreased continuously. When the mass fraction of MPP powder in the mixture is 70%, the explosion of polypropylene dust with a mass concentration of 300 g/m3 is completely inhibited. Thermogravimetric analysis showed that the addition of MPP powder increased the decomposition temperature and thermal stability of polypropylene. Combined with the test results of thermal analysis, the explosive suppression mechanism of MPP powder was discussed, and the analysis showed that MPP powder had physical and chemical inhibition effects.

Key words: dust explosion; polypropylene; melamine polyphosphate; suppression