Investigation of mechanical and frictional performance for bismaleimide composites reinforced by hyperbranched polysiloxane-cyclophosphazene functionalized rGO/MoS₂

In this article, graphene/MoS₂ nanosheets (rGO/MoS₂) functionalized by a novel hyperbranched polysiloxane (HBPSi) containing cyclophosphazene (HBPSi-CPP) were synthesized by a precipitation polymerization approach. We doped different loading amounts of HBPSi-CPP@rGO/MoS₂ as solid lubricating filler into bismaleimide (BMI) resin to produce HBPSi-CPP@rGO/MoS₂/BMI hybrid composite materials. The morphology and structure of HBPSi-CPP@rGO/MoS₂ as well as the mechanical and tribological properties of BMI composites were systematically investigated. The results exhibited that 0.8 wt% BMI system got the peak values of the bending and impact strengths (187.8 MPa and 22.4 kJ/m²), which are the highest values of rGO-based materials for BMI matrix in open literatures. Moreover, for 0.4 wt% BMI sample, its average frictional coefficient and abrasion rate get the minimum values of 0.26 and 1.6 × 10⁻⁶ mm³/(N·m), separately. This is attributed to the good dispersibility and self-lubrication of HBPSi-CPP@rGO/MoS₂ as well as the improved inorganic-organic compatibility between HBPSi-CPP@rGO/MoS₂ nanomaterial and BMI resin.