Lignin-containing coatings for packaging materials—pilot trials
2021 (English)In: Polymers, E-ISSN 2073-4360, Vol. 13, no 10, article id 1595
Article in journal (Refereed) Published
Abstract [en]
One severe weakness of most biopolymers, in terms of their use as packaging materials, is their relatively high solubility in water. The addition of kraft lignin to starch coating formulations has been shown to reduce the water solubility of starch in dry coatings. However, lignin may also migrate into aqueous solutions. For this paper, kraft lignin isolated using the LignoBoost process was used in order to examine the effect of pH level on the solubility of lignin with and without ammonium zirconium carbonate (AZC). Machine-glazed (MG) paper was coated in a pilot coating machine, with the moving substrate at high speed, and laboratory-coated samples were used as a reference when measuring defects (number of pinholes). Kraft lignin became soluble in water at lower pH levels when starch was added to the solution, due to the interactions between starch and lignin. This made it possible to lower the pH of the coating solutions, resulting in increased water stability of the dry samples; that is, the migration of lignin to the model liquids decreased when the pH of the coating solutions was reduced. No significant difference was observed in the water vapor transmission rate (WVTR) between high and low pH for the pilot-coated samples. The addition of AZC to the formulation reduced the migration of lignin from the coatings to the model liquids and led to an increase in the water contact angle, but also increased the number of pinholes in the pilot-coated samples. © 2021 by the authors
Place, publisher, year, edition, pages
MDPI AG , 2021. Vol. 13, no 10, article id 1595
Keywords [en]
Barrier coatings, Glycerol, Lignin, Starch, Biopolymers, Coatings, Contact angle, Solubility, Zirconium compounds, Coating machines, Coating solution, High solubility, Starch coatings, Water contact angle, Water solubilities, Water stability, Water vapor transmission rate, Packaging materials, Mass Transfer, Water Vapor Permeability
National Category
Polymer Technologies
Identifiers
URN: urn:nbn:se:ri:diva-54368DOI: 10.3390/polym13101595Scopus ID: 2-s2.0-85106576528OAI: oai:DiVA.org:ri-54368DiVA, id: diva2:1568927
Note
Funding details: Karlstads universitet, KAU; Funding details: VINNOVA, 2015-05023; Funding details: Stiftelsen för Kunskaps- och Kompetensutveckling, KKS, 20100268; Funding text 1: This work was performed as part of the multidisciplinary Industrial Graduate School VIPP (Value Created in Fibre-based Processes and Products) at Karlstad University. Financial support from The Knowledge Foundation (Sweden), grant registration number 20100268, and from Vinnova (Sweden?s innovation agency), grant registration number 2015-05023, is gratefully acknowledged.The authors thank J.A. Bristow for the linguistic revision of the manuscript and testbed LignoCity operated by RISE LignoDemo AB for the delivery of kraft lignin. UMV Coating Systems AB, S?ffle, Sweden, is gratefully acknowledged for the pilot coating trials.; Funding text 2: Funding: This work was performed as part of the multidisciplinary Industrial Graduate School VIPP (Value Created in Fibre-based Processes and Products) at Karlstad University. Financial support from The Knowledge Foundation (Sweden), grant registration number 20100268, and from Vinnova (Sweden’s innovation agency), grant registration number 2015-05023, is gratefully acknowledged.
2021-06-182021-06-182024-01-17Bibliographically approved