Photo-crosslinkable poly (vinyl alcohol)/nanocrystalline cellulose composites with controllable performance and exceptional water vapor barrier property for packaging application

Photo-crosslinkable poly (vinyl alcohol)- g -glycidyl methacrylate/cellulose nanocrystal- g -methacrylic anhydride (PVA- g -GMA/CNC- g -MA) composites were developed through solution casting. After UV crosslinking, a significant increase of 137% in tensile strength, a decrease of 65.45% in water absorption, and a decrease of 34.3% (in 98% relative humidity) in water vapor barrier property were obtained for the PVA- g -GMA/10% CNC-g-MA composite compared to those of pure PVA, exhibiting excellent mechanical, water resistance, and noticeable humidity stability. It is because UV photo-crosslinking significantly improves the interaction between PVA- g -GMA and CNC- g -MA in PVA- g -GMA/CNC- g -MA composites even under high humidity. In addition, CNC- g -MA was evenly distributed in the PVA- g -GMA matrix in PVA- g -GMA/10% CNC- g -MA composites, and the hydrophobicity of MA and GMA endows the PVA- g -GMA/10% CNC- g -MA composites with low surface hydrophobicity and excellent water resistance, water vapor barrier property and barrier stability in high humidity. Overall, a new, effective, and environment-friendly method for the preparation of PVA/CNC based composite is demonstrated, offering a great value in packaging applications. Graphical abstract Photo-crosslinkable poly (vinyl alcohol)- g -glycidyl methacrylate/cellulose nanocrystal- g -methacrylic anhydride (PVA- g -GMA/CNC- g -MA) composites were developed through solution casting. After UV crosslinking, PVA- g -GMA/CNC-g-MA composites possessed excellent mechanical, water resistance, noticeable humidity stability, and low surface hydrophobicity. Schematic diagram of photo-crosslinking of PVA- g -GMA and CNC- g -MA.