The compatibilities of polymer binder hydroxyl-terminated polybutadiene (HTPB) with plasticizer dioctyl sebacate (DOS), nitroglycerine (NG) of solid propellants were simulated by molecular dynamics (MD) simulations and mesoscopic dynamics (MesoDyn) simulations. Density, cohesive energy density (CED) and solubility parameters (δ) of pure substances and HTPB/Plasticizer blends, Flory-Huggins (χ) interaction parameters and binding energies between the system components were calculated by MD simulations with the COMPASS force field. By comparing the difference in the solubility parameter values (Δδ) and the change of density, the compatibility of the polymer binder with the plasticizer could be predicted, the HTPB/plasticizer interaction and its essence were clarified by calculating binding energy. χ interaction parameters calculated from MD simulations were converted into MesoDyn input parameters, the mesoscale morphologies of blends and the dynamic evolution process of the system were investigated by MesoDyn simulations, and the compatibility could be predicted by analyzing isosurface of the density fields, order parameters and free energy density. Results show that HTPB/DOS is a miscible system but HTPB/NG is not miscible, and the predictions agreed well with experimental observations.

Key words: binder hydroxyl-terminated polybutadiene (HTPB), plasticizer, compatibility, molecular dynamics simulation, mesoscopic dynamics simulation