Enhancing the Anti-Migration Performance and Mechanical Properties of EPDM Insulation through Functionalized GO

The excessive migration of small molecular plasticizers in solid propellants may lead to debonding and changes in combustion characteristics, affecting the safety of solid rocket motors. Herein, two functionalized graphene oxides (GO) were used to enhance the anti-migration performance of EPDM insulation. GO, 3-Aminopropyltriethoxysilane-modified GO (AGO) and octadecylamine-modified GO (HGO) were filled into EPDM to fabricate EPDM insulation. The anti-migration properties and migration kinetics of EPDM insulations were studied using immersion tests. Moreover, the mechanical properties, including the tensile properties, crosslink density, hardness, and aging resistance of different EPDM insulations, were also explored. Compared with GO, AGO, and HGO obviously enhanced the anti-migration and mechanical properties of the EPDM insulations. This study shows that the anti-migration performance of EPDM insulation can be enhanced by functionalized GO.

Improvement in Migration Resistance of Hydroxyl-Terminated Polybutadiene (HTPB) Liners by Using Graphene Barriers

The excessive migration of plasticizers leads to debonding and cracking of a liner, which can compromise the safety of a solid propellant. Graphene oxide (GO), with a laminar structure as a filler, can effectively reduce the migration of plasticizers. In this study, we modified GO using toluene diisocyanate (TDI). The cross-link density of the substrate was increased by grafting isocyanate groups to obtain a denser liner for the purpose of preventing plasticizer migration. We also used octadecylamine (ODA) to modify GO by grafting negatively charged amide groups on the GO surface. The electrostatic repulsive effect of the amide group on the plasticizer molecules was used to prevent plasticizer migration. Two modified GOs were filled into the hydroxyl-terminated polybutadiene to prepare two composite liners. We then investigated the migration resistance and migration kinetics of each modified liner using the dipping method. In addition, we explored the mechanical properties of each modified liner. Compared with the original liner, the anti-migration and mechanical properties of the modified composite liners were significantly improved. Among them, the TDI-modified liner had the most obvious improvement in migration resistance, while the ODA-modified liner had the greatest improvement in bonding properties. All types of liners met the requirements of the current propellant systems. This study provides an effective reference for improving the migration resistance and bonding properties of the composite liner.

Influence of the Binder Structure on the Interfacial Adhesion and Antimigration Properties of the Propellant Charge

Maintaining the structural integrity of solid rocket propellant charges has been widely concerned by scholars around the world. The introduction of a polyester transition layer between the propellant and the liner is a new and effective method used to improve the interfacial bonding properties of the solid propellant charge and inhibit the migration of high-energy plasticizers. Uniaxial tensile pull-off specimens and accelerated aging experiments at multiple temperatures were used to study the interfacial bonding properties of propellant charges and the migration properties of plasticizers, respectively. The influence of the polyester structure on the two properties was also discussed in detail, and a targeted antimigration mechanism was proposed based on the molecular structure of the plasticizer. In addition, the Weibull model was used to fit the plasticizer migration behavior, and the plasticizer migration master curve in the charge system was obtained based on the principle of time-temperature superposition, which broadens the application field of the model and is important from an application perspective.