Sustainable multi-purpose bacterial cellulose composite for food packaging via facile successive infiltration

Petroleum-based plastic packaging materials have been widely used, causing severe environmental impacts. To address this challenge, there is an urgent need to develop biodegradable materials that offer strong mechanical and excellent barrier properties while ensuring food safety. In this study, sustainable, high-performance film derived from bacterial cellulose (BC) through a straightforward and eco-friendly water-based successive infiltration process is developed. To enhance the transparency and haze of BC specimens for better visual detection, waterborne polyurethane (WPU) is infiltrated for refractive index compensation and serves as an adhesive. Subsequently, the mechanical strength and water resistance of the BC/WPU films are improved by incorporating a seaweed extract, sodium alginate (SA), and metal ion chelation (Ca 2+ , Al 3+ , and Zr 4+ ). The resulting BC/WPU/[email protected] film exhibited low hygroscopicity (+53.5 % after 190 h of immersion), high transparency (90.01 %) and excellent haze (10.91 %), exceptional tensile strength (82.8 MPa) and modulus (6.96 GPa), low gas permeability (OP = 0.0137 mL-mm/m²-day-atm and WVP = 8.75 g-mm/m²-day-atm), high biodegradability (85.23 % weight loss in 49 days), high flexibility, formability, and great heat sealability. These outstanding features make the BC/WPU/[email protected] film exceptionally well-suited for advanced and versatile packaging applications. Several examples were also demonstrated to show its exceptional potential for packaging applications.