Citric or Acetic Acid Effects on the Crosslinking of PVOH

Transportation and shipping processes are the most dangerous times for food due to harsh handling and frequent temperature changes. Plain corrugated boxes cannot withstand the damp environment caused by melting ice that is used to keep foods cold and fresh. To minimize damage, a protective polymer film coating can be applied. These coatings can be unsafe when used with food and will lead to excess waste by limiting the recyclability of the boxes. The purpose of this project was to produce nontoxic crosslinked PVOH films to determine suitability for a cost effective, biodegradable, and repulpable corrugated box coating. Polyvinyl alcohol (PVOH) was blended with two different organic acid solvents - citric acid and acetic acid – at various concentrations to be cast into thin polymer films and characterized for barrier properties. Intermolecular interactions were investigated using FTIR, TGA, and DSC analysis. Successful crosslinking with the citric acid at different concentrations resulted in property changes that suggest certain PVOH/citric acid blends are suitable for corrugated box coatings. Property changes with PVOH/acetic acid films did not indicate successful crosslinking. Elucidation of the results and further sample production by the Industrial Technology and Packaging graduate program will seek to field test and confirm these experimental outcomes in practice. Overall, the research and testing showed that this solution is possible