The effects of thermal pyrolysis and decomposition products on explosive characteristics of flufenacet and sulfentrazone

Thermal pyrolysis and decomposition products of flufenacet and sulfentrazone powders were tested by thermogravimetric analysis (TGA), TGA coupled with Fourier transform infrared spectroscopy and pyrolysis-gas chromatography/mass spectrometry. Besides, the explosion sensitivity (minimum ignition temperature, minimum ignition energy, minimum explosion concentration) and explosion severity (maximum explosion pressure, and the maximum rate of pressure rise) were measured in standard 20-L spherical chamber, Hartmann apparatus and Godbert-Greenwald Furnace apparatus. Moreover, the effect of thermal pyrolysis characteristics on the explosion sensitivity and severity of flufenacet and sulfentrazone dust clouds were analyzed. The results indicated that flufenacet had lower decompose temperature, and smaller activation energy than sulfentrazone. Both flufenacet and sulfentrazone expressed flammable and toxic substance during their decomposition. Greater amount of products with higher flammability were expressed from flufenacet compared with sulfentrazone. The flufenacet had lower explosion sensitivity than sulfentrazone In addition, the flufenacet's explosion severity was higher than sulfentrazone, which was mainly determined by the larger number of combustible gases from flufenacet. What's more, both the two herbicide powders can lead to serious dust explosion accidents due to their explosive and toxic characteristics.