Development of catechol-functionalized chitosan/poly(vinyl alcohol) nanocomposite films incorporated with dual network coated layered clay for active packaging applications

In order to solve the problems of traditional plastic packaging materials like poor degradability and insufficient active packaging function, this study successfully designs and synthesizes tannic acid (TA)-titanium (Ti) dual network coated hydrotalcite-like layered clay (LDHs@TA-Ti) and catechol grafted chitosan (C-CS) based on the principle of mussel bionics. And a novel idea is first put forward to fabricate LDHs@TA-Ti/C-CS/polyvinyl alcohol (PVA) nanocomposite films by solution casting method. The result of infrared and thermal analysis indicate that strong interfacial interaction is formed in the nanocomposites, which leads to the limitation of molecular chain movement and the increase of glass transition temperature. Although the addition of LDHs@TA-Ti significantly increases the crystallization temperature, the crystallinity does not change significantly. The water resistance, UV barrier, tensile strength and antibacterial properties of the final nanocomposite films are improved significantly, and all the films show good transparency in the visible range. Especially when the addition amount of LDHs@TA-Ti reaches 1 wt%, compared with C-CS/PVA composite film, the UV (at 300 nm) barrier property and tensile strength are increased by 36.3% and 45.1% respectively. Therefore, LDHs@TA-Ti/C-CS/PVA nanocomposite films show great potential as environmentally friendly active packaging films or coatings in extending the shelf life of food products.

Automated summary

This study successfully designed and synthesized novel nanocomposite films based on mussel bionics, prepared LDHs@TA-Ti/C-CS/PVA nanocomposite films by solution casting method, and improved water resistance, UV barrier, tensile strength, and antibacterial properties while maintaining good transparency.