“Brick-and-Mortar” multidimensional sodium alginate composite films reinforced with ginger residue nanocellulose for high-performance biodegradable packaging

Developing biodegradable packaging materials with strong mechanical strength and reliable barrier performance is essential for reducing reliance on petroleum-based plastics and promoting sustainable food packaging. In this study, ginger residue-derived nanocellulose (GNC) was extracted via sulfuric acid hydrolysis and combined with two-dimensional nanomaterials montmorillonite (MMT) and alkyl ketene dimer (AKD) to construct Brick-and-Mortar-like multidimensional sodium alginate (SA)-based composite films. For the ternary composite system, response surface methodology was used to optimize the formulation, yielding an optimal composition of 5.2% GNC, 7.6% MMT, and 9.2% AKD (SA-GMA). The obtained SA-GMA film exhibited a significant relationship between structure and performance: including a reduction in oxygen permeability to 2.274 cm³ /m²·24 h·0.1 MPa, a decrease in water vapor permeability to 5.289 × 10⁻⁷ g·m/m²·h·Pa, and an increase in tensile strength to 62.39 MPa. Structural and spectroscopic analyses revealed that GNC and MMT synergistically reinforced the polymer matrix through a compact layered architecture, while AKD improved hydrophobicity via β-keto ester bond formation and the distribution of hydrophobic droplets. These combined effects endowed the composite films with enhanced barrier and mechanical properties. Overall, this work provides an effective strategy for valorizing agricultural waste and developing high-performance bio-based packaging materials with potential in sustainable packaging applications.