Preparation and Characterization of Chemically Crosslinked Polyvinyl Alcohol/Carboxylated Nanocrystalline Cellulose Nanocomposite Hydrogel Films with High Mechanical Strength

Chemically crosslinked polyvinyl alcohol (PVA)/carboxylated nanocry-stalline cellulose (PVA/CNCC) nanocomposite hydrogel films were fabricated by film-casting of PVA/CNCC mixture solutions and subsequent thermal-curing of the PVA with the CNCC. Gel fractions of the hydrogel films were measured to confirm the occurrence of crosslinking. Morphologies of the hydrogel films were characterized by polarized light microscopy and scanning electron microscopy (SEM). Thermal properties, swelling behavior and mechanical properties of the hydrogel films were investigated to evaluate the influence of CNCC content (10～30% of PVA mass). Equilibrium water content of the hydrogel films was in the range of 40～49%. At swelling equilibrium, the hydrogel films could be stretched to 3～3.4 times their original length, and their tensile strength was in the range of 7.9～11.6 MPa. The results show that the PVA/CNCC nanocomposite hydrogel films were both extensible and highly tough.