Per- and Polyfluoroalkyl substances (PFAS’s) are widely used to coat paper and cardboard for food packaging because of their desirable grease, water, and heat resistant properties. However, the US FDA has raised concerns regarding the safety of these materials, citing the potential of degradation products to persist in rodents after repeated exposure, and known health risks of similar molecules. 1 In recent years, the US FDA and the EPA have reached agreements with several major manufacturers to phase out certain PFAS-containing food contact substances. 2,3 This necessitates a replacement for some food package coatings. Recently, many materials that are suitable for food contact have been developed, though the scope of this seminar is limited to four paper coatings. Coating paper with polysiloxane using melamine as a primer imparts hydrophobic characteristics onto the paper surface. 4 Biowax-silica hybrids with protein additives can be used to create superhydrophobic nanocomposites on paper surfaces. 5 Applying sodium alginate/propylene glycol alginate solutions to paper surfaces can impart both hydrophobic and oleophobic qualities. 6 Lignin-containing cellulose nanofibrils can create an oil barrier when applied to paper surfaces. 7 Herein, these alternatives are described and evaluated based on their hydrophobicity, oleophobicity, manufacturing ease, and other desirable properties.
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2. U.S. Food & Drug Per and Polyfluoroalkyl Substances (PFAS). https://www.fda.gov/food/chemicals/and-polyfluoroalkyl-substances-pfas.
3. U.S. EPA Fact Sheet: 2010/2015 PFOA Stewardship Program.
4. Li, Z.; Rabnawaz, M. Fabrication of Food-Safe Water-Resistant Paper Coatings Using a Melamine Primer and Polysiloxane Outer Layer. ACS Omega 2018, 3, 11909-11916.
5. Wan, J.; Wang, P.; Qian, X.; Zhang, M.; Song, S.; Wang, M.; Guo, Q.; Shen, J. Bioinspired Paper-Based Nanocomposites Enabled by Biowax–Mineral Hybrids and Proteins. ACS Sustainable Chem. Eng. 2020, 8, 9906-9919.
6. Sheng, J.; Li, J.; Zhao, L. Fabrication of grease resistant paper with non-fluorinated chemicals for food packaging. Cellulose 2019, 26, 6291-6302.
7. Tayeb, A.,H.; Tajvidi, M.; Bousfield, D. Paper-Based Oil Barrier Packaging using Lignin-Containing Cellulose Nanofibrils. Molecules 2020, 25.