Molecular Dynamics Simulation of the Influence of PEG‐TDI Aging Degradation on Diffusibility and Compatibility of NG and BTTN

Abstract

AbstractIn this study, the molecular dynamics method was used to explore the effects of the degradation of an adhesion agent (PEG‐TDI) in a nitrate ester plasticized polyether propellant on the compatibility and diffusibility of energetic plasticizers (NG and BTTN) and the glass transition temperature and mechanical properties of the blend system (PEG‐TDI/NG/BTTN). The radial distribution function, the mean square radius of gyration, and fractional free volume of the PEG‐TDI/NG/BTTN system under different degrees of degradation conditions were calculated. The diffusibility and compatibility of NG and BTTN, the glass transition temperature, and the mechanical properties of the blended system were then discussed. The results showed that, with aggravation of the degree of PEG‐TDI degradation, the fractional free volume in the system decreased, intermolecular hydrogen bonding and van der Waals interactions enhanced, and the size of the polymeric nematic decreased. These changes eventually caused the diffusion ability of NG and BTTN to weaken, compatibility to be enhanced, and glass transition temperature, stiffness, and yield strength of the PEG‐TDI/NG/BTTN system to increase.