A reconstructed cellulose packaging with heat dissipating and water-resistant properties for functional applications

Food packaging waste is alarming for the environment as they are often thrown away after a short consumption. Using food packaging waste resources to reconstruct a packaging material is a promising choice for sustainable development and environmental protection with low energy consumption, low cost, and sustainability. Herein, this work presents a novel nano-reconstruction strategy to reconstruct the hydrophobic cellulose@Mg-Al layered double hydroxide (hydrophobic reconstructed packaging) via one-step in-situ growth of MgAl layered double hydroxide (LDH) nanosheets on the food packaging waste, followed by hydrophobic modification. The obtained hydrophobic reconstructed packaging not only preserves the intrinsic mechanical properties of the packaging material but also upgrades it to achieve both heat dissipation and water resistance functions. In the outdoor test, it was demonstrated that the hydrophobic reconstructed packaging can be up to 5.8 °C and 4.6 °C cooler than commercial cellulose packaging under sunny and cloudy days, respectively, which can reduce the impact of high temperatures on products inside the packaging. Due to hydrophobic modification, the hydrophobic reconstructed packaging has outstanding water resistance (water contact angle: 133°) and suitability in both acid-base and solar irradiation environments, which offer a guarantee for packaging material to adapt the fluctuating environment during packaging applications. Simultaneously, the surface structural and chemical properties of material confer hydrophobic reconstructed packaging excellent self-cleaning, anti-ultraviolet, and mechanical properties. Overall, this work provides a promising approach to address environmental concerns and promote sustainable practices in waste management with practical significance in real-world applications, while proposing forward-looking ideas for the exploration of advanced techniques to upgrade food packaging waste into functional materials.