Experimental study on the thermal decomposition and combustion characteristics of nitrocellulose with different alcohol humectants

Although the thermal behaviors including thermal instability of nitrocellulose (NC) and its mixtures with some humectants have been comprehensively examined previously in the literature, their combustion characteristics have not been systematically studied. To address the issue, the combustion properties of NC with alcohol humectants are investigated by the means of the ISO 5660 cone calorimeter. Two kinds of NC-humectant mixtures with 30 wt.% isopropanol and 30 wt.% ethanol, respectively, were employed as samples. The tests were conducted under different external radiations, ranging from 0-15 kW/m2. The experimental results indicate that the external radiation positively influences the peak heat release rate (HRR) intensity and the maximum mass loss rate (MLR), while the total heat release (THR) decreases with the elevated external radiation. Comparatively, the sample with isopropanol exhibits a higher fire risk, characterized by the higher peak HRR, THR and maximum MLR. Auxiliary investigating methods, including Scanning Electron Microscopy and Differential Scanning Calorimeter-Thermal Gravimetric Analysis, were applied to examine the micro structure and thermal behavior of NC-humectant mixtures. The results helped to explain the burning characteristics observed in the cone calorimeter tests.