Micro-fibrillated lignocellulose films for high-performance sustainable packaging

Nanocellulosic materials, including nanofibers and microfibers, are promising sustainable alternatives for packaging due to their biodegradability, excellent film-forming ability, and robust mechanical performance. In this study, we produced microfibrillated lignocellulose (MFLC) from bleached chemithermomechanical aspen pulp using low-consistency refining (LCR) as a promising material for sustainable packaging. The MFLC was then converted into high-strength, water-resistant films with unique dual wettability—hydrophobic on one side and hydrophilic on the other—through casting, drying, and hot pressing. This opposing wettability naturally arises from the intrinsic hydrophobicity of lignin and its high interfacial energy with water, causing nano-lignin particles to accumulate at the film surface during formation. This feature provides promising potential for advanced packaging applications. Key packaging metrics—including mechanical strength, water vapor transmission rate, porosity, and thermal stability—were characterized. Increased thickness improved tensile strength and tear resistance, whereas hot pressing further improved tensile strength and thermal stability but reduced flexibility. These findings highlight MFLC produced though LCR as a promising precursor for bio-based packaging materials, particularly when high strength, thermal stability, and controlled surface hydrophilicity are required.