Towards a new generation of functional fiber-based packaging: cellulose nanofibers for improved barrier, mechanical and surface properties

The present work shows the suitability of using industrial fluting papers as raw material for the development of four different substrates, enzymatically refined and/or containing cellulose nanofibers (CNF) in bulk. These four substrates were deeply studied and treated with different coating formulations, containing CNF, polyvinyl alcohol (PVA), native starch and alkyl ketene dimer, with the purpose of evaluating the benefits of using fiber-based packaging paper with improved mechanical, physical and barrier properties. The results showed that if CNF are coated in combination with PVA the tensile properties of paper can be significantly improved, as well as the grease resistance, whereas the air permeability and water vapor transmission rate decrease. The obtained papers present interesting vapor and air barrier properties, at the same time that unconceivable limits of breaking length are achieved (6.44 km). In addition, when a second layer of alkyl ketene dimer was coated on both sides of paper, the water contact angle was significantly improved, being higher than 115°. Overall, the present work shows the feasibility of recycled fibers for the production of high value-added papers that can be used for packaging purposes due to their improved barrier and mechanical properties, and contributes therefore for the bio-based circular economy.