2025 AIChE Annual Meeting

Strategic Cosolvent Polarity Tuning Enables Additive Uptake in Cellulose for Eco-Friendly Packaging Applications

Plastic packaging accounts for nearly 40% of global plastic waste, much of which persists in the environment and leaches synthetic additives into soil and water. Biodegradable alternatives are urgently needed to mitigate these impacts. Cellulose, the most abundant natural polymer, is a renewable and degradable candidate for sustainable packaging. However, cellulose requires modification to enhance durability and functional properties. Previous studies have examined impregnation of bioactive molecules into cellulose using supercritical CO₂ (scCO₂), but limited work has evaluated how cosolvent polarity influences sorption efficiency. In addition, the potential of vanillin, a natural compound with antioxidant and UV-absorbing properties, to improve cellulose’s performance has not been systematically evaluated. Addressing this gap, our study investigates cosolvent-assisted vanillin sorption into cellulose using scCO₂.

This study investigates the hypothesis that cosolvent polarity can be strategically manipulated to facilitate intermolecular interactions with cellulose, thereby enhancing vanillin sorption during supercritical impregnation. Gravimetric analysis measured vanillin sorption across nonpolar (heptane [non-H-bonding]), moderately polar (acetone [H-bond accepting], isopropanol [H-bonding accepting/donating]), and polar (water [H-bonding accepting/donating]) cosolvents. Results show that heptane and water facilitated minimal vanillin uptake (0.03 g/g), while acetone and isopropanol achieved the highest uptake (0.54 g/g), demonstrating the importance of intermediate polarity. Acetone’s unique balance of polarity and non–H-bonding capability made it particularly effective in enhancing sorption. These findings suggest that cosolvent selection is a critical parameter for optimizing SCI, with an emphasis in the use of moderately polar solvents. By improving UV resistance and stability of cellulose papers with vanillin impregnation, this work advances the development of sustainable packaging with enhanced performance. Future optimization of concentration, temperature, and process duration will support scalable applications with broad societal and environmental benefits.