A novel polyamide-type cyclophosphazene functionalized rGO/WS2 nanosheets for bismaleimide resin with enhanced mechanical and tribological properties

Bismaleimide (BMI) composites reinforced with novel polyamide-type cyclophosphazene functionalized rGO/WS2 were successfully fabricated in this paper. RGO/WS2 was firstly functionalized with polyphosphazene (poly(cyclophosphazene-co-branched polyethylenimine)) (PHbP) by a simple precipitation polymerization approach. The microstructure and morphology of as-prepared PHbP@rGO/WS2 were characterized detailedly. The mechanical and tribological properties of virgin BMI and its composites with various amounts of nano-filler (0.2-1.0 wt%) were comparatively investigated. The largest improvements in impact and flexural strengths of BMI composite (21.2 kJ/m(2) and 185.7 MPa, respectively) were observed when the content of PHbP@rGO/WS2 was only 0.8 wt% and 0.6 wt%, increased by 82.8% and 52.0% than those of pure BMI. Furthermore, 0.6 wt% BMI system exhibited the lowest friction coefficient (0.13) and volume wear rate (1.22 x 10(-6) mm(3)/(N.m)), decreased by 69.0% and 92.6% than neat BMI. This is owing to the good dispersibility and self-lubricity of PHbP@rGO/WS2, strong interfacial strength between filler and BMI matrix.