AUTOCLAVING CELLULOSE NITRATES OBTAINED FROM FRUIT SHELLS OF OATS

Besides the targeted viscosity decrease, the high-temperature autoclaving of cellulose nitrates (CNs) can provide one of the key properties - chemical stability - which governs the operational process safety and guaranteed shelf life of CN-based products. Here we report the study results of the autoclaving of cellulose nitrates derived by esterification of pulp with mixed sulfuric-nitric acids. The pulp was obtained from an easily renewable domestic feedstock - oat hulls - agroindustrial residue. On the basis of experiments, regression relationships are suggested herein that enable the prediction of basic properties of CNs, depending on autoclaving time. The optimum high-temperature autoclaving time was identified that allows oat-hull CNs to be produced with the following characteristics: 12.14% nitrogen content, 12 mPa.s viscosity and 98% solubility in alcohol-ether mixture, which are similar to the characteristics of dinitrocellulose (Colloxyline-N). Ampule chromatography confirmed that the resultant CNs had a high chemical stability. The quantity of nitrogen oxide from thermal decomposition of CNs (90 degrees C, 192 h) was found to be 0.35 ml/g and was not above the permissible level for dinitrocellulose. Differential scanning calorimetry revealed that the oat-hull CNs are characterized by a high onset temperature of decomposition (200 degrees C) and a high specific heat of decomposition (7.36 kJ/kg), indicating a high chemical purity of the resultant product. The findings presented herein justify the use of oat-hull CNs in the manufacture of gun-propellant grains and composite explosives.