Study on the Melting Process of Nitrocellulose by Thermal Analysis Method

Abstract

The melting process of NC is studied by using modulated differential scanning calorimetry (MDSC) technique, the microscope carrier method for measuring the melting point and the simultaneous device of the solid reaction cell in situ/RSFT-IR. The results show that the endothermic process in the MDSC curve is reversible. It is caused by the phase change from solid to liquid of the mixture of initial NC, decomposition partly into condensed phase products. The values of the melting point, melting enthalpy (ΔH_m), melting entropy (ΔS_m), the enthalpy of decomposition (ΔH_dec) and the heat-temperature quotient (ΔS_dec) obtained by the MDSC curve of NC at a heating rate of 10 K min⁻¹ are 476.84 K, 205.6 J g⁻¹, 0.4312 J g⁻¹ K⁻¹, −2475.0 J g⁻¹ and −5.242 Jg⁻¹K⁻¹, respectively. The MDSC results of NC with different nitrogen contents show that with increasing the nitrogen content in NC, the absolute values of ΔH_m, ΔS_m, ΔH_dec and ΔS_dec increase.