Synergistic effect of novel hyperbranched polysiloxane and Ti₃C₂T_x 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 Ti₃C₂T_x 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 polycondensation 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.