Recent progress in polyvinyl alcohol (PVA)/nanocellulose composite films for packaging applications: A comprehensive review of the impact on physico-mechanical properties

As society advances, the demand for innovative and sustainable food processing techniques and materials has grown significantly. The food industry, especially the food packaging sector, faces the challenge of developing cost-effective and sustainable packaging materials to meet consumers' increasing demands. One promising solution for this is the use of biodegradable polymers such as polyvinyl alcohol (PVA), but standalone PVA cannot meet the required properties of packaging materials. The use of nanocellulose (NC) as fillers has been intensively studied recently. This review article provides a comprehensive overview of existing studies focusing on the preparation of PVA/NC composite films for packaging applications. The effects of NC loading on the physico-mechanical properties of these films, including tensile strength, elongation, water absorption/swelling behavior, barrier properties, and optical properties, have been thoroughly examined. Overall, the general findings suggest that the reinforcement of NC in the PVA polymer matrix leads to improvements in the films' properties. Specifically, the addition of NC enhances tensile strength, reduces O₂, CO₂, and water vapor transmission rates, and decreases the films' propensity to absorb moisture or swell under wet conditions. However, it is important to note that the presence of NC compromises the optical properties of the films by reducing transparency, and the NC content beyond threshold level reduces the feasibility of the composite film. By synthesizing these findings, this review underscores the potential of PVA/NC composite films as promising materials for packaging applications. Moving forward, further research efforts are warranted to optimize the formulation and processing of these composite films to strike a balance between mechanical strength and optical clarity, thus advancing their practical utility in the packaging industry.