Enhanced anti-plasticizer migration in GO/EPDM insulation for composite solid propellants: Experimental study and molecular dynamics simulation

Ethylene–propylene–diene monomer (EPDM) is widely used as an insulation in composite solid propellants. However, the migration of plasticizers from the propellant into the insulation seriously affects the long-term reliability. In this study, graphene oxide (GO)/EPDM insulation were prepared and their anti-migration behavior against typical plasticizers, including dioctyl sebacate (DOS), N-butyl-N-(2-nitroxyethyl) nitramine (Bu-NENA), and nitroethyl nitrate (En), was systematically investigated. The incorporation of GO significantly reduced the migration of plasticizers through nanobarrier mechanism. Migration experiments showed that the overall performance was optimized at a GO content of 3 phr. Compared with pure EPDM, the equilibrium migration amount of DOS decreased to 37.17%, Bu-NENA to 24.69%, and En to 41.86%. Dynamic mechanical analysis confirmed higher storage modulus and lower tan δ, while contact angle tests revealed reduced wettability to plasticizers, both evidencing stronger interfacial interactions and weaker thermodynamic compatibility. SEM and XRD demonstrated that GO nanosheets were well dispersed, constructing tortuous diffusion pathways. Molecular dynamics simulations (MD simulations) further verified the mechanism, showing that the diffusion coefficient of DOS decreased by ∼ 32% in GO/EPDM, and binding energy analysis indicated reduced compatibility between plasticizers and the GO/EPDM. This research provide a practical route for designing high-performance anti-migration insulation.