1. Improving the Barrier Properties of Paper to Moisture, Air, and Grease with Nanocellulose-Based Coating Suspensions
- Author
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André Mazega, Quim Tarrés, Roberto Aguado, Maria Àngels Pèlach, Pere Mutjé, Paulo J. T. Ferreira, Marc Delgado-Aguilar, and Agencia Estatal de Investigación
- Subjects
air resistance ,alginate ,barrier properties ,Kit rating ,minerals ,nanocellulose ,packaging paper ,poly(vinyl alcohol) ,pullulan ,water vapor transmission rate ,General Chemical Engineering ,Paper -- Fabricació ,Papermaking ,Paper -- Embalatge ,Paper -- Packing ,General Materials Science ,Materials nanoestructurats ,Nanostructured materials - Abstract
Food packaging manufacturers often resort to lamination, typically with materials which are neither non-biodegradable nor biobased polymers, to confer barrier properties to paper and cardboard. The present work considers a greener solution: enhancing paper’s resistance to moisture, grease, and air by aqueous coating suspensions. For hydrophobization, a combined approach between nanocellulose and common esterifying agents was considered, but the water vapor transmission rate (WVTR) remained excessively high for the goal of wrapping moisture-sensitive products (>600 g m−2 d−1). Nonetheless, oil-repellant surfaces were effectively obtained with nanocellulose, illite, sodium alginate, and/or poly(vinyl alcohol) (PVA), reaching Kit ratings up to 11. Regarding air resistance, mineral-rich coatings attained values above 1000 Gurley s. In light of these results, nanocellulose, minerals, PVA, pullulan, alginate, and a non-ionic surfactant were combined for multi-purpose coating formulations. It is hypothesized that these materials decrease porosity while complementing each other’s flaws, e.g., PVA succeeds at decreasing porosity but has low dimensional stability. As an example, a suspension mostly constituted by nanocellulose, sizing agents, minerals and PVA yielded a WVTR of roughly 100 g m−2 d−1, a Kit rating of 12, and an air resistance above 300 s/100 mL. This indicates that multi-purpose coatings can be satisfactorily incorporated into paper structures for food packaging applications, although not as the food contact layer The authors wish to acknowledge the financial support of the Spanish Ministry of Science and Innovation to the projects CON‐FUTURO‐ES (PID2020‐113850RB‐C22) and NextPack (PID2021‐124766OA‐I00)
- Published
- 2022
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