Synergistic effect of novel hyperbranched polysiloxane and Ti3C2Tx MXene/MoS2 hybrid filler towards desirable mechanical and tribological performance of bismaleimide composites

Despite two-dimensional (2D) layered MoS2 and newly emerging lamellar MXene providing great potential in lubricity, the mechanical and tribological performance of their hybrids in polymeric composites has been rarely discussed. Herein, the Ti3C2Tx MXene/MoS2 hybrids were successfully prepared by a hydrothermal method, and a novel hyperbranched polysiloxane (HBPSi) terminated by amino groups was synthesized by a one-pot poly-condensation reaction. The mechanical and tribological properties of bismaleimide (BMI) composites as well as their wear mechanisms were systematically evaluated using HBPSi as reinforced phase and MXene/MoS2 as lubrication additive. The results show that the addition of HBPSi and MXene/MoS2 hybrids dramatically improved mechanical strengths and tribological performance. Specifically, the 8 wt% HBPSi and 0.6 wt% MXene/MoS2 hybrid filler enhanced impact and flexural strengths by 85% and 42%, and decreased the frictional coefficient and wear rate by 69% and 88%, respectively, with neat BMI resin as a comparison. The splendid mechanical and tribological performance is ascribed to the synergistic effect of "soft" toughening HBPSi and "hard" lubricating MXene/MoS2, the good dispersion of hybrid filler, and the formed protective tribo-film. This work paves a way for the design and application of novel high-performance lubrication additive in the polymeric matrix.