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Christophliemk, H., Bohlin, E., Emilsson, P. & Järnström, L. (2023). Surface Analyses of Thin Multiple Layer Barrier Coatings of Poly(vinyl alcohol) for Paperboard. Coatings, 13(9), Article ID 1489.
Open this publication in new window or tab >>Surface Analyses of Thin Multiple Layer Barrier Coatings of Poly(vinyl alcohol) for Paperboard
2023 (English)In: Coatings, ISSN 2079-6412, Vol. 13, no 9, article id 1489Article in journal (Refereed) Published
Abstract [en]

The hypothesis of the present study is that thin multiple layer coatings on paperboard from the aqueous solutions of poly(vinyl alcohol) (PVOH) at high machine speeds is more effective in terms of barrier properties than one or two thick layers. The objectives included attempts to use surface roughness parameters to understand the coating process and mechanisms behind coating defects. The present study is focused on pilot-scaled PVOH coating onto uncoated paperboard at machine speeds of 400 m/min. The multiple coating operation was carried out in six passes with a dry coat weight of about 1 g/m2 in each layer. The concept of thin multiple coatings resulted in coated surfaces without detected pinholes and with Kit rating 12 after only two thin layers. However, the oxygen transmission rates were still fairly high (100 & PLUSMN; 89 cm3/m2 day atm) after six layers, and some coating defects (such as craters and cracks) could be identified. The analyses of surface structure indicated that the surface properties are affected by water uptake during the coating processes. The compression of paperboard beneath the metering element seemed to be required to achieve homogeneous thin layers. However, an analysis of defects revealed flaws and inhomogeneities near objects protruding from the surface, such as surface fibers and craters, caused by blistering. For rough paperboard substrates, the desired barrier properties may require a careful balance between sufficient compression for fiber coverage and gentle compression in order to avoid defects near craters and surface fibers.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
paper coating, polyvinyl alcohol, barrier properties, multilayer coating, topographic analysis, morphological analysis
National Category
Paper, Pulp and Fiber Technology
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-97098 (URN)10.3390/coatings13091489 (DOI)001073385500001 ()2-s2.0-85172788749 (Scopus ID)
Available from: 2023-10-19 Created: 2023-10-19 Last updated: 2023-10-20Bibliographically approved
Winestrand, S., Järnström, L. & Jönsson, L. (2021). Fractionated lignosulfonates for laccase-catalyzed oxygen-scavenging films and coatings. Molecules, 26(20), Article ID 6322.
Open this publication in new window or tab >>Fractionated lignosulfonates for laccase-catalyzed oxygen-scavenging films and coatings
2021 (English)In: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, Vol. 26, no 20, article id 6322Article in journal (Refereed) Published
Abstract [en]

Lignin derivatives have potential as antioxidants in advanced packaging materials through their ability to scavenge oxygen in reactions catalyzed by phenol-oxidizing enzymes, such as laccase. The effects of size fractionation of lignosulfonates on laccase-catalyzed reactions were investigated in experiments with aqueous solutions, films, and coated paperboard. Four industrial lignosulfonate preparations were compared: Feed (unfractionated), Prod (5–60 kDa enriched), Conc (≥60 kDa enriched), and Perm (≤60 kDa enriched). Extraction of lignosulfonates from films showed that the enzymic reaction increased the average molecular weight from <10,000 to up to 66,000. The enzymatic reaction resulted in an increase in the water contact angle of the films from the range 25–49◦ to 56–81◦. The four preparations showed relatively small differences with regard to their ability to scavenge oxygen in aqueous solution and in experiments with coated paperboards in sealed chambers. Coatings with lignosulfonates where the contents of low-molecular weight material had been reduced (i.e., Prod and Conc) showed improved water resistance after the enzymic reaction. Thus, in both aqueous and solid media, fractionation of lignosulfonates had little effect on oxygen scavenging, but fractionation was beneficial for other reasons, such as improved cross-linking resulting in higher molecular weight and superior water resistance.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
Active packaging, Coating, Laccase, Lignin, Lignosulfonates, Oxygen scavenging, Paperboard, antioxidant, excipient, lignosulfuric acid, oxygen, phenol derivative, water, catalysis, chemistry, infrared spectroscopy, molecular weight, oxidation reduction reaction, procedures, Antioxidants, Excipients, Oxidation-Reduction, Phenols, Spectroscopy, Fourier Transform Infrared
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-88811 (URN)10.3390/molecules26206322 (DOI)000794102200001 ()2-s2.0-85117489972 (Scopus ID)
Available from: 2022-02-28 Created: 2022-02-28 Last updated: 2023-08-28Bibliographically approved
Javed, A., Ullsten, H., Rättö, P. & Järnström, L. (2021). Lignin-containing coatings for packaging materials: Pilot trials. Polymers, 13(10), Article ID 1595.
Open this publication in new window or tab >>Lignin-containing coatings for packaging materials: Pilot trials
2021 (English)In: Polymers, E-ISSN 2073-4360, Vol. 13, no 10, article id 1595Article 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.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
barrier coatings, glycerol, lignin, starch
National Category
Chemical Engineering
Research subject
Chemical Engineering; Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-66850 (URN)10.3390/polym13101595 (DOI)000655155600001 ()2-s2.0-85106576528 (Scopus ID)
Funder
Knowledge Foundation, 20100268Vinnova, 2015-05023
Note

Artikeln ingick som manuskript i Javeds (2018) doktorsavhandling Effects of plasticizing and crosslinking on coatings based on blends of starch-PVOH and starch-lignin. 

Available from: 2018-03-26 Created: 2018-03-26 Last updated: 2024-01-17Bibliographically approved
Gozali, E., Järnström, L., Papadikis, K. & Idris, A. (2020). Numerical Modeling of a Short-Dwell Coater for Bio-Based Coating ApplicationsCoatings. Coatings, 11(1), Article ID 13.
Open this publication in new window or tab >>Numerical Modeling of a Short-Dwell Coater for Bio-Based Coating ApplicationsCoatings
2020 (English)In: Coatings, ISSN 2079-6412, Vol. 11, no 1, article id 13Article in journal (Refereed) Published
Abstract [en]

Computational fluid dynamics (CFD) simulations were used for the evaluation of critical issues associated with coating processes with the aim of developing and optimizing this important industrial technology. Four different models, namely, the constant viscosity, shear thinning, Oldroyd-B viscoelastic, and Giesekus models, were analyzed and compared in a short-dwell coater (SDC) using a bio-based coating material. The simulation results showed that the primary vortex formations predicted by the viscoelastic models were highly dependent on the flow Deborah number, resulting in uneven stress distribution over the coated surface. For the viscoelastic models, the dominance of elastic forces over viscous forces gave rise to significant normal stress difference, primarily along the surface of the substrate paper. The shear-thinning phenomena predicted by the Giesekus model, however, tended to relax the stress development in contrast to the Oldroyd-B model. The observations indicate that a reduced coating velocity or modification of the coating material with a reduced relaxation time constant can significantly enhance the uniformity and thickness of the coating over the coated surface under controlled conditions.

Place, publisher, year, edition, pages
MDPI, 2020
Keywords
bio-based materials; Giesekus model; Oldroyd-B model; short-dwell coater viscoelasticity
National Category
Fluid Mechanics and Acoustics
Research subject
Chemical Engineering; Mechanical Engineering
Identifiers
urn:nbn:se:kau:diva-82055 (URN)10.3390/coatings11010013 (DOI)000610014500001 ()2-s2.0-85098890564 (Scopus ID)
Available from: 2020-12-28 Created: 2020-12-28 Last updated: 2022-05-11Bibliographically approved
Breen, C., Clegg, F., Thompson, S., Järnström, L. & Johansson, C. (2019). Exploring the interactions between starches, bentonites and plasticizers in sustainable barrier coatings for paper and board. Applied Clay Science, 183, Article ID 105272.
Open this publication in new window or tab >>Exploring the interactions between starches, bentonites and plasticizers in sustainable barrier coatings for paper and board
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2019 (English)In: Applied Clay Science, ISSN 0169-1317, E-ISSN 1872-9053, Vol. 183, article id 105272Article in journal (Refereed) Published
Abstract [en]

Effective food packaging is a major factor in the current global drive to minimise food waste. Starch is an excellent oxygen barrier for packaging but it is brittle and moisture sensitive. The addition of layered minerals and plasticizers can significantly improve the moisture barrier and flexibility of the resulting composite. Some combinations of starch and plasticizer are incompatible but our results show that the addition of bentonite ensures the formation of coherent starch films with much improved moisture barrier regardless of the starch-plasticizer compatibility. It was clearly demonstrated that improvement of the moisture barrier was critically dependent on the layer charge of the bentonite used. Starch was readily accommodated in the interlayer space of bentonites with a layer charge of <0.4 electrons per formula unit but was not adsorbed if the layer charge was above this value. Starch-bentonite-plasticizer coatings prepared using bentonites with the lower layer charge routinely produced higher barriers to water vapour. The water vapour transmission rate (WVTR) of the base paper was reduced from 780 to 340 ± 20 g m2 day−1 when coated with starch alone. This was further reduced to 48 or 66 g m2 day−1 if glycerol or lower charge bentonite, respectively, was added to the starch. Optimised coatings of starch-lower charge bentonite-plasticizer provided WVTR values of ≤10 g m2 day−1 whereas WVTR values for comparative coatings prepared using the higher charge bentonites were three to four times higher (35 ± 7 g m2 day−1). Scanning electron micrographs provided clear evidence for the presence of 60 nm thick supramolecular layers formed from starch-bentonite-plasticizer in the samples coated on either glass or paper. The WVTR values for these low-eco footprint coatings are competitive with proprietary coatings prepared using petroleum derived resins.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Barrier coating, Bentonite, Layer charge, SEM, Starch, X-ray diffraction, Coatings, Moisture, Plasticizers, Reinforced plastics, Scanning electron microscopy, Solvents, Water vapor, X ray diffraction, Barrier coatings, Interlayer spaces, Moisture barriers, Paper and boards, Scanning electron micrographs, Supramolecular layers, Transmission rates, resin, Vapor Barriers
National Category
Chemical Sciences
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-75726 (URN)10.1016/j.clay.2019.105272 (DOI)000506426500001 ()2-s2.0-85073156077 (Scopus ID)
Available from: 2019-11-12 Created: 2019-11-12 Last updated: 2020-01-23Bibliographically approved
Mesic, B., Cairns, M., Järnström, L., Le Guen, M. J. & Parr, R. (2019). Film formation and barrier performance of latex based coating: Impact of drying temperature in a flexographic process. Progress in organic coatings, 129, 43-51
Open this publication in new window or tab >>Film formation and barrier performance of latex based coating: Impact of drying temperature in a flexographic process
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2019 (English)In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 129, p. 43-51Article in journal (Refereed) Published
Abstract [en]

The post-application behaviour of aqueous dispersion barrier coatings is investigated. We have adapted a dispersion formulation initially optimised for rod coating, for application to linerboard by a flexographic press. The clay/talc/wax/poly(styrene-butadiene) latex dispersion coatings demonstrated a 60% reduction in water vapour transport rate across the barrier, and a 75% reduction in direct water uptake when the applied film was dried at 75 degrees C. Multi-layer coatings with a combined application rate of 7 g m(-2) exhibited Cobb(120) direct water uptake of 16.3 +/- 3.7g m(-2) (120s water contact duration) and a water vapour transport rate of 140 +/- 12g m(-2) d(-1) (23 degrees C, 50% RH). Investigation of the post-coating curing regime demonstrated a decrease in the prevalence of crack defects within the cured film, and corresponding improvement in barrier properties when higher drying temperatures were employed. Dynamic mechanical analysis of the cured films indicated improvements in homogeneity and a greater extent of intermolecular interactions in the coating formulations cured at elevated temperatures.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Barrier coating, Dispersion, Latex film formation, Flexography, WVTR, Cobb
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-71725 (URN)10.1016/j.porgcoat.2018.12.025 (DOI)000460495800006 ()
Available from: 2019-04-05 Created: 2019-04-05 Last updated: 2019-04-10Bibliographically approved
Javed, A., Rättö, P., Järnström, L. & Ullsten, H. (2018). Crack analysis of barrier coatings based on starch and starch-PVOH with and without plasticizer. Nordic Pulp & Paper Research Journal, 33(2), 336-347
Open this publication in new window or tab >>Crack analysis of barrier coatings based on starch and starch-PVOH with and without plasticizer
2018 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 33, no 2, p. 336-347Article in journal (Refereed) Published
Abstract [en]

Barrier coatings based on starch and starch-PVOH plasticized with glycerol and without plasticizer were applied to two different paperboard substrates, a triple coated board and duplex board, in order to investigate the tendency for cracks to develop in the barrier coating layers during creasing and folding. Tensile properties of films based on the starch and starch-PVOH blend were determined to investigate the relationship between the flexibility of the films and the cracking in the barrier coating layers. Furthermore, the oxygen transmission rate through the barrier-coated paperboard was measured before and after creasing and folding. The oxygen transmission rate through the barrier-coated samples was over the measurable range i. e. OTR>10000cm3/m2day after creasing and folding, which indicated failure in the barrier coating layers. Optical microscopy revealed small cracks in the barrier coating layers, probably related to an increase in flexibility of the barrier coating layers. It was observed in scanning electron micrographs that cracks in the barrier coating layers seemed to follow the fibers when the barrier coating was applied on the rear side of the duplex board. Scanning electron micrographs and surface profiler images revealed that cracks in the barrier coating layers might have originated from the mineral coating layer when the starch and starch/PVOH coating layers were applied on the mineral-coated side of the triple coated board. An increase in the thickness of the barrier coating layer did not seem to increase the resistance to failure.

Place, publisher, year, edition, pages
Walter de Gruyter, 2018
Keywords
Starch, Glycerol, Barrier coatings, Mechanical properties, Creasing, Folding
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-66849 (URN)10.1515/npprj-2018-3039 (DOI)000450922400018 ()
Available from: 2018-03-26 Created: 2018-03-26 Last updated: 2024-02-07Bibliographically approved
Javed, A., Rättö, P., Järnström, L. & Ullsten, H. (2018). Lignin-containing coatings for packaging materials. Nordic Pulp & Paper Research Journal, 33(3), 548-556
Open this publication in new window or tab >>Lignin-containing coatings for packaging materials
2018 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 33, no 3, p. 548-556Article in journal (Refereed) Published
Abstract [en]

The mechanical properties and chemical stability in water of self-supporting films made from aqueous solutions of starch and lignin, and the barrier properties of paperboard coated with solutions of these polymers have been studied. The dissolution of starch from the starch-lignin films in contact with the model liquids was decreased significantly when lignin was added to the starch films. The addition of ammonium zirconium carbonate (AZC) to the formulations as a crosslinking agent substantially increased the storage modulus of the starch-lignin films, which indicated that crosslinking had occurred. The addition of AZC to the formulations also led to a decrease in dissolution of both starch and lignin from the starch-lignin films in contact with model liquids. The effect of AZC on the water stability of the films was greater when the pH of the starch-lignin-AZC solution was adjusted with ammonia rather than NaOH. The addition of NH4Cl solution as a presumed catalyst to the recipe when the pH adjustment was performed with NaOH did not improve the effect of AZC on the water stability of the films. The water vapour transmission rate of the coated paperboard decreased slightly when AZC was added to the coating formulation.

Place, publisher, year, edition, pages
Walter de Gruyter, 2018
Keywords
barrier coatings, glycerol, lignin, mechanical properties, starch
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-66852 (URN)10.1515/npprj-2018-3042 (DOI)000450923900021 ()
Note

Artikeln ingick som manuskript i Javeds doktorsavhandling Effects of plasticizing and crosslinking on coatings based on blends of starch-PVOH and starch-lignin

Available from: 2018-03-26 Created: 2018-03-26 Last updated: 2024-02-07Bibliographically approved
Petkova-Olsson, Y., Oelschlaeger, C., Ullsten, H. & Järnström, L. (2018). Structural, microrheological and kinetic properties of a ternary silica-Pluronic F127-starch thermosensitive system. Journal of Colloid and Interface Science, 514, 459-467
Open this publication in new window or tab >>Structural, microrheological and kinetic properties of a ternary silica-Pluronic F127-starch thermosensitive system
2018 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 514, p. 459-467Article in journal (Refereed) Published
Abstract [en]

Hypothesis: The sol-gel transition in aqueous suspensions consisting of silica particles and thermosensitive polymer is controlled by inter-particle forces and solution properties of the polymer. Addition of a second non-thermosensitive polymer may affect the transition. The purpose of this work was to characterize the kinetics of the sol-gel transition and to understand the effects of a second non-thermosensitive polymer on the microstructure, using a combination of classical rheology and microrheology. Experiments: Classical rotational rheology as well as two microrheology methods, Multiple Particle Tracking (MPT) and Diffusing Wave Spectroscopy (DWS), were used to investigate the sol-gel transition of a ternary silica-Pluronic F127-starch thermosensitive system. Findings: Classical rheometry and DWS indicated sol-gel transition temperature similar to 25 degrees C at 1 wt% Pluronic, independently of the concentration of the other components. DWS showed a fast gelation process, less than two minutes for all samples, beside a second slow kinetic process. In the gel state, MPT indicated micro-structural and micro-viscoelastic differences compared to rotational rheology. This was explained by formation of an elastic matrix of silica and polymers in combination with assembly of silica particles in large macroporous agglomerates. Presence of starch led to breakdown of the macro porous network, leaving the homogeneous elastic network left.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Thermosensitive; Silica-pluronic-starch; Sol-gel transition; Kinetic; Microrheology; Microstructure
National Category
Chemical Sciences
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-66616 (URN)10.1016/j.jcis.2017.12.051 (DOI)000424963700050 ()29289030 (PubMedID)
Available from: 2018-03-08 Created: 2018-03-08 Last updated: 2019-10-23Bibliographically approved
Nyflött, Å., Petkova-Olsson, Y., Moons, E., Bonnerup, C., Järnström, L., Carlsson, G., . . . Minelli, M. (2017). Modelling of oxygen permeation through filled polymeric layers for barrier coatings. Journal of Applied Polymer Science, 134(20), Article ID 44834.
Open this publication in new window or tab >>Modelling of oxygen permeation through filled polymeric layers for barrier coatings
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2017 (English)In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 134, no 20, article id 44834Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Wiley-Blackwell, 2017
National Category
Polymer Technologies Composite Science and Engineering
Research subject
Materials Science
Identifiers
urn:nbn:se:kau:diva-47461 (URN)10.1002/app.44834 (DOI)000395129600020 ()
Funder
Knowledge FoundationStora Enso
Available from: 2016-12-13 Created: 2016-12-07 Last updated: 2022-03-30Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1256-1708

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