Structure and Mechanical Performance of Poly(vinyl Alcohol) Nanocomposite by Incorporating Graphitic Carbon Nitride Nanosheets

Owing to the high aspect ratio, the two-dimensional (2D) inorganic nanofillers have attracted extensive interest in the field of polymer reinforcement. In this work, graphitic carbon nitride (g-C₃N₄) nanosheets were obtained via thermal condensation of melamine and were then ultrasonically exfoliated in water, which was confirmed by atomic force microscopy (AFM) and TEM. Poly(vinyl alcohol) (PVA)/g-C₃N₄ nanocomposites were achieved by solution casting using water as the solvent. The structure and mechanical performance of PVA/g-C₃N₄ nanocomposites were studied. It was found that the g-C₃N₄ nanosheets were well dispersed in the PVA matrix. The introduction of g-C₃N₄ nanosheets increased the glass transition temperature and crystallinity of the nanocomposites, leading to the improved mechanical performance. Compared with the pure PVA, the PVA/g-C₃N₄ nanocomposite with 0.50 wt% g-C₃N₄ nanosheets showed ~70.7% enhancement in tensile strength, up from 51.2 MPa to 87.4 MPa.