Volatility of NENA and Other Energetic Plasticizers determined by thermogravimetric analysis

Abstract

AbstractThermogravimetric analysis (TGA) at constant temperature was used to measure weight loss of plasticized nitrocellulose (NC) propellants due to vaporization of plasticizer. Plasticizers consisted of three 2‐nitroxyethylnitramine (NENA) compounds, diethylene glycol dinitrate (DEGDN), and nitroglycerin (NG). Initial concentration of plasticizer and degree of nitration of NC were also varied. Each propellant was tested at three temperatures. Plasticizer diffusivities (D) and their activation energies were calculated. Observed trends were generally consistent with calculated plasticizer solubility parameters, expected increases in molecular mobility for more highly plasticized materials, and the more polar and more disordered structure of NC with a lower degree of nitration. Some unexpected effects could be explained by changes in entropy of activation due to variation in plasticizer or NC structure. In general, the NENA plasticizers had lower vaporization rates than DEGDN or NG, suggesting that plasticizer losses during manufacturing or storage of practical formulations should not be a problem.