MXene/sPS nanocomposites: rheological, electrical conductivity, polymorphism, mechanical, thermal, and flammability...

MXenes as an emerging class of 2D materials have great potential in fabricating functional polymer nanocomposites. In this study, Ti₃C₂T MXene as a representative MXene filler was employed to prepare sPS nanocomposites. The abundant surface groups (mainly -OH) on MXene allowed facile modification, and thus MXene nanosheets bearing -C₁₂H₂₅ groups were prepared using dodecyl triethoxysiloxane (DCTES) as a modifier. Grafting -C₁₂H₂₅ long alkyl chains onto the surface of MXene strongly affected its affinity towards hydrophobic solvent and the sPS matrix. The rheological threshold concentration (ϕ _c, = 0.033 vol%) and exponent (β = 1.51) and the conductivity threshold concentration (ϕ _c, = 0.259 vol%) and exponent (β = 2.92) were determined by applying percolation scaling laws. The influences of DCTES-modified MXene on the polymorphism, mechanical, thermal and flammability properties of nanocomposites were studied. The obtained nanocomposites displayed not only enhanced mechanical properties, but also improved thermal stability and flame retardancy to some extent. Moreover, the higher the loading level of DCTES-modified MXene, the better was the improved effect.