Synergistic compatibilization of PA12/PPO blends by PPO- <i>g</i> -MA and graphene oxide: mechanical, thermal, and flame-retardant properties

In this study, polyamide 12 (PA12)/poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) blends with a mass ratio of 90/10 were compatibilized using maleic anhydride-<i>grafted</i>-PPO (PPO-<i>g</i>-MA), graphene oxide (GO), and their combinations to enhance the interface compatibility and improve the mechanical, thermal, and flame-retardant properties of the PA12/PPO blends. The effects of the compatibilizers on the blends' morphology, mechanical behavior, dynamic mechanical properties, thermal stability, and flame retardancy were investigated. The glass transition temperatures of the blends using the compatibilizers showed shifts compared to the neat blend, indicating that the compatibility of PA12 and PPO in these blends was improved. The dual compatibilizer system significantly enhanced the dispersion and interfacial interaction, leading to synergistic improvements, thereby improving the mechanical strength, thermal stability, and flame retardancy of the blend compared to the blend using each compatibilizer individually. The blend sample using 3% PPO-<i>g</i>-MA and 1% GO achieved a tensile strength of 48.6 MPa, impact strength of 47.3 kJ m^-2 compared to 29.3 MPa and 33.1 kJ m^-2 of the neat PA12/PPO blend, respectively. The thermal stability of the blends was also enhanced by the simultaneous addition of both PPO-<i>g</i>-MA and GO. Besides, the enhanced thermal stability was directly reflected in flame resistance, with the limiting oxygen index (LOI) increasing from 21.9% to 24.6% and the UL-94 rating improving from V2 to V1.