Effect of inorganic salt on the thermal degradation of nitrocellulose and reaction mechanism of its mixture

In this study,to better understand the reaction mechanism between inorganic salts and nitrocellulose,CaCO_(3) and Li_(2)CO_(3) were evaluated with respect to their effects on the thermal degradation of NC in nitrogen atmosphere using TG/DSC at three different heating rates(2,5,10 K/min).The numerical relationship between activation energy(E)and conversion rate was obtained by FWO and KAS method,and it was discovered that CaCO_(3) could improve the thermal stability of NC.Activation energy values were calculated by Kissinger method,and it was found that NC that contain Li2CO3had the highest activation energy while NC containing CaCO3had the lowest E value.By combining the thermal analysis data with Malek method,the most probable mechanism model of thermal degradation is obtained as Sesták-Berggren model,which expression is f(α)=α^(m)(1-α)^(n).As a result of this study,there are certain guiding principles that can be applied to the pyrolysis reaction model and to the actual production process of nitrocellulose.

Researches on Thermal Decomposition Kinetics of Composite Modified Double-base Propellants

The thermal decomposition kinetics of composite modified double-base （CMDB） propellants with a series of contents of hexogeon （RDX） was investigated by using parameters of Tco, Ti, Tp, Tf, Tb, Ta, E, lg A and AH, which were obtained from using a CDR-4P differential scanning calorimeter （DSC） and Perkin-Elmer Pyris l thermogravimetric analyzer （TG） analyses with heating rates of 5, 10, 15 and 20 K/min. Reliable activation energy was calculated using Flynn-Wall-Ozawa method before analyzing the thermal decomposition mechanism. TG-DTG curves were treated with Malek method in order to obtain the reaction mechanisms. The obtained results show that the thermal decomposition mechanisms with the conversion from 0.2 to 0.4 was f（a）= 1/2a, and with the conversion from 0.5 to 0.7 was f（a）=（1/4）（1--a）[--1n（1 --a）]-3.