This review explores recent advances in the mechanical reinforcement of polymer nanocomposites using 2D nanofillers, focusing on the mechanisms of reinforcement, evaluation of model and bulk nanocomposites, and the effects of hybrid filler combinations.

The fabrication of eco-friendly and high-performance composite materials has gained significant attention for multifunctional applications. Polyvinyl alcohol (PVA)/starch composite films containing varying amounts of Ti₃C₂T_x MXene (2.5-10 wt%) were produced using a simple casting method. The impact of MXene nanoplatelets on the films' chemical structure and physical properties were thoroughly analysed. It was revealed that MXene formed hydrogen bonding with the polymer matrix and tended to align in the plane of the films. The mechanical properties of the PVA/starch blend were significantly improved with increasing MXene loading. With 10 wt% MXene, the Young's modulus (YM) and tensile strength (TS) increased by 669 % (from 255.7 to 1965.3 MPa) and 292 % (from 9.2 to 36.1 MPa), respectively. Additionally, the presence of MXene greatly improved the films' water and oxygen barrier properties, reducing water vapor permeability (WVP) by 91 % and oxygen permeability (OP) by 79 %. These improvements are attributed to the homogeneous dispersion of MXene within the blend and the interfacial interactions between the components. Furthermore, the PVA/starch/MXene composite films exhibited excellent recyclability, maintaining their mechanical and barrier properties even after recycling, demonstrating their potential for repeated use without performance loss. Overall, the developed composite films present a promising sustainable solution for applications in materials requiring advanced mechanical and barrier performance.