Functional Oxygen Barriers for Food Packaging from Biomass-Derived Materials

There is a strong drive to discover and develop alternatives to conventional plastics that offer the ability to be manufactured and used in a circular manner. In a circular economy, as opposed to a linear one, materials are derived from renewable resources or recycled content, and at the end of life, they are able to be circulated back into production via a chemical, physical or biological pathway. A critical need exists to develop such materials for plastic packaging, which represents the largest contributor to unrecyclable or difficult-to-recycle plastic waste. This seminar will describe recent innovations in preparation of barrier films and coatings, suitable for food or pharmaceutical packaging, based on combinations of cellulose- and chitin-based nanomaterials. Cellulose nanocrystals (CNCs) and chitin nanofibers (ChNFs) are oppositely-charged, water-dispersible fibers that are abundant and could form the basis of a platform of renewable, high-performance materials. Because of their high crystalline content, they are of interest for use in barrier packaging. The combination of CNCs and ChNFs to produce alternating layered materials, direct blends, and other composites, results in high barrier properties to oxygen, driven by electrostatics and hydrogen bonding-driven densification. Current challenges are discussed as well, including the improvement to sensitivity to water vapor and manufacturability.