Strengthening, toughing and thermally stable ultra-thin MXene nanosheets/polypropylene nanocomposites via nanoconfinement

Developing high-performance polymer nanocomposites with outstanding heat resistance and high strength, and superior ductility is vital for their practical applications. However, it is a great challenge to achieve simultaneous improvements in the strength and ductility due to the presence of antagonistic mechanisms in the both parameters. Nanoconfinement structure affording heat resistance and high strength, and good extensibility is inspired by the natural world, such as spider web, silkworm net, and honeycomb consisting of three-dimensional networks generated by vast hydrogen bonds. Here, we reported the methods of oxygen-free fast drying assisted solution casting and melt blending for fabricating advanced ultrathin two-dimensional (2D) titanium carbide (Ti₃C₂T_x)/polypropylene nanocomposites with significantly enhanced initial degradation temperature (79.1 °C increase), tensile strength (35.3% increase), ductility (674.6% increase) and storage modulus (102.2% increase). The thermal stability and mechanical properties improvements induced by Ti₃C₂T_x nanosheets are superior to those of similar 2D nanomaterials, such as graphene, molybdenum disulfide, montmorillonite, layered double hydroxide, and even 1D carbon nanotubes because of the combination of H-bonds induced nanoconfinement structure with the physical barrier effect of ultrathin Ti₃C₂T_x nanosheets. This work provides a facile nanoconfinement-inspired strategy for the design of thermally stable, mechanical strong and ductile polymer materials and a paradigm for broadening the application of 2D MXenes in polymeric materials.