Anti-migration of NG by using EPDM insulation materials coated with reduced graphene oxide

The migration of nitroglycerin (NG) has always been the critical issue that harmfully impacts the structural integrity and operational reliability of the solid rocket motor, which is mainly composed by Nitrate Ester Plasticized Polyether (NEPE) propellant/Hydroxyl-terminated Polybutadiene (HTPB) liner/Ethylene Propylene Diene Monomer (EPDM) insulation bonding system. This paper proposes an innovative surface modification method attempting to modify the EPDM insulation layer coated with reduced graphene oxide (RGO), which exhibits ability to weaken the NG absorption by EPDM insulation layer, blocking the pathway of NG migration into EPDM insulation materials. The microstructure of RGO-coated layer was analyzed and the formation mechanism was investigated. The RGO-coated layer is well bonded to the HTPB liner, and its anti-migration performance to NG at different temperatures has been evaluated. Comparing with blank samples under the same storage conditions, the RGO-coated layers can reduce the diffusion coefficient of NG by up to 87.3% and increase the diffusion activation energy of NG by 14.8 kJ⋅mol⁻¹. This research provides a new strategy to effectively inhibit NG migration in NEPE propellant/HTPB liner/EPDM insulation bonding system.