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Structure-Performance Relations of Oxygen Barriers for Food Packaging
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Food packaging should ensure the safety and quality of food, minimize spoilage and provide an easy way of storing and handling it. Barrier coatings are generally used to meet the demands placed on fibre-based food packages, as these have the ability to regulate the amount of gases that can enter them. Some gases are detrimental to food quality: oxygen, for example, initiates lipid oxidation in fatty foods. Using both experimental data and computer modelling, this thesis explains some aspects of how the structure of barrier coatings influences the mass transport of oxygen with the aim of obtaining essential knowledge that can be used to optimize the performance of barriers.

Barrier coatings are produced from polyvinyl alcohol and kaolin blends that are coated onto a polymeric support. The chemical and physical structures of these barriers were characterized according to their influence on permeability in various climates. At a low concentration of kaolin, the crystallinity of polyvinyl alcohol decreased; in the thinner films, the kaolin particles were orientated in the basal plane of the barrier coating. The experimental results indicated a complex interplay between the polymer and the filler with respect to permeability.

A computer model for permeability incorporating theories for the filled polymeric layer to include the polymer crystallinity, addition of filler, filler aspect ratio and surrounding moisture was developed. The model shows that mass transport was affected by the aspect ratio of the clay in combination with the clay concentration, as well as the polymer crystallinity. The combined model agreed with the experiments, showing that it is possible to combine different theories into one model that can be used to predict the mass transport.

Four barrier coatings: polyethylene, ethylene vinyl alcohol + kaolin, latex + kaolin and starch were evaluated using the parameters of greenhouse gas emissions and product costs. After the production of the barrier material, the coating process and the end-of-life handling scenarios were analysed, it emerged that starch had the lowest environmental impact and latex + kaolin had the highest.

Abstract [en]

Food packaging is required to secure the safety and quality of food, as well as minimize spoilage and simplify handling. Barrier coatings are generally used to meet the demands placed on fibre-based food packages, as these have the ability to regulate the amount of gases that can enter them. Some gases are detrimental to food quality: oxygen, for example, initiates lipid oxidation in fatty foods.

This thesis focuses on the mass transport of oxygen in order to gain deeper knowledge of, and thereby optimise, the performance of barrier coatings. This experimental study, together with computer modelling, characterized the structure of barrier materials with respect to the mass transport process. The performance of the barriers was evaluated based on the parameters of environmental impact and product costs. As the long-term aim is to use non-petroleum-based barrier coatings for packaging, these should be evaluated by assessing the properties of the material in question, its functionality and its environmental impact to provide more insight into which materials are desirable as well as to develop technology.

The results from this study indicate that several parameters (the orientation, concentration and aspect ratio of the clay and the polymer crystallinity) influence the properties of a barrier. Using this knowledge, researchers and food packaging engineers can work toward improving and customising renewable barriers.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2017. , p. 100
Series
Karlstad University Studies, ISSN 1403-8099 ; 2017:3
Keywords [en]
Barrier coating, Permeability, Dynamic Mass Transport, Modelling, Diffusion, Polymer, Dispersion, Kaolin, LCA, Starch, Hemicellulose
National Category
Polymer Technologies Textile, Rubber and Polymeric Materials Computational Mathematics Food Engineering Composite Science and Engineering Paper, Pulp and Fiber Technology
Research subject
Materials Science
Identifiers
URN: urn:nbn:se:kau:diva-47496ISBN: 978-91-7063-738-4 (print)ISBN: 978-91-7063-739-1 (electronic)OAI: oai:DiVA.org:kau-47496DiVA, id: diva2:1055814
Public defence
2017-02-10, Eva Eriksson, 21A342, Karlstad, 10:00 (English)
Opponent
Supervisors
Projects
VIPP
Funder
Knowledge Foundation, 20100268Stora EnsoAvailable from: 2017-01-24 Created: 2016-12-13 Last updated: 2019-07-11Bibliographically approved
List of papers
1. Influence of kaolin addition on the dynamics of oxygen mass transport in polyvinyl alcohol dispersion coatings
Open this publication in new window or tab >>Influence of kaolin addition on the dynamics of oxygen mass transport in polyvinyl alcohol dispersion coatings
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2015 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 30, no 3, p. 385-392Article in journal (Refereed) Published
Abstract [en]

The permeability of dispersion barriers produced from polyvinyl alcohol (PVOH) and kaolin clay blends coated onto polymeric supports has been studied by employing two different measurement methods: the oxygen transmission rate (OTR) and the ambient oxygen ingress rate (AOIR). Coatings with different thicknesses and kaolin contents were studied. Structural information of the dispersion-barrier coatings was obtained by Fourier transform infrared spectroscopy (FTIR) spectroscopy and scanning electron microscopy (SEM). These results showed that the kaolin content influences both the orientation of the kaolin and the degree of crystallinity of the PVOH coating. Increased kaolin content increased the alignment of the kaolin platelets to the basal plane of the coating. Higher kaolin content was accompanied by higher degree of crystallinity of the PVOH. The barrier thickness proved to be less important in the early stages of the mass transport process, whereas it had a significant influence on the steady-state permeability. The results from this study demonstrate the need for better understanding of how permeability is influenced by (chemical and physical) structure.

Keywords
Barrier coating, Dynamic mass transport, Kaolin, Permeability, Polyvinyl alcohol
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-34457 (URN)10.3183/NPPRJ-2015-30-03-p385-392 (DOI)000361615500002 ()
Funder
Knowledge Foundation
Note

Ingår i lic.uppsats Structural Studies and Modelling of Oxygen Transport in Barrier Materials for Food Packaging som manuskript med titeln: Influence of kaolin addition in polyvinyl alcohol dispersion coating on the dynamics of oxygen mass transport.

Available from: 2014-10-22 Created: 2014-10-22 Last updated: 2019-07-10Bibliographically approved
2. The influence of clay orientation and crystallinity on oxygen permeation in dispersion barrier coatings
Open this publication in new window or tab >>The influence of clay orientation and crystallinity on oxygen permeation in dispersion barrier coatings
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2016 (English)In: Applied Clay Science, ISSN 0169-1317, E-ISSN 1872-9053, Vol. 126, p. 17-24Article in journal (Refereed) Published
Abstract [en]

In this study oxygen permeability in dispersion barriers produced from poly(vinyl alcohol) (PVOH) and kaolin clay blends coated onto polymeric supports was investigated. To determine the oxygen permeability, two measurement methods were used: the oxygen transmission rate (OTR) and the ambient oxygen ingress rate (AOIR). It was found that with increasing kaolin content the oxygen permeability increased, up to about 5 wt% kaolin, whereafter the oxygen permeability decreased, as was expected. The increased (> 5%) kaolin loading lowered the diffusion because of an increased tortuosity. Structural information about the dispersion-barrier coatings, such as kaolin orientation and polymer crystallinity, was obtained from Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Kaolin orientation was influenced by the drying temperature, the thickness of the samples, and the kaolin concentration. The polymer crystallinity increased in thicker samples. The drying temperature did not show any clear effect on the crystallinity of thin samples, while for the thicker barriers, combined with a kaolin concentration lower than 20 wt%, a higher crystallinity was achieved at lower drying temperatures. This study demonstrates the strong influence of chemical and physical structures on the permeability of the investigated coatings.

Keywords
Barrier coating; Kaolin; Polyvinyl alcohol; Permeability; Dynamic mass transport; Crystallinity; Kaolin orientation
National Category
Chemical Engineering Composite Science and Engineering
Research subject
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-41069 (URN)10.1016/j.clay.2016.02.029 (DOI)000376213900003 ()
Funder
Knowledge Foundation, 20100268
Available from: 2016-03-16 Created: 2016-03-16 Last updated: 2022-03-30Bibliographically approved
3. Modelling of oxygen permeation through filled polymeric layers for barrier coatings
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
4. The influence of moisture content on the polymer structure of polyvinyl alcohol in dispersion barrier coatings and its effect on the mass transport of oxygen
Open this publication in new window or tab >>The influence of moisture content on the polymer structure of polyvinyl alcohol in dispersion barrier coatings and its effect on the mass transport of oxygen
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2017 (English)In: JCT Research, ISSN 1547-0091, E-ISSN 2168-8028, p. 1345-1355Article in journal (Refereed) Published
Abstract [en]

This paper presents a study of the effect of moisture on the gas permeability of polyvinyl alcohol (PVOH) and PVOH–kaolin dispersion barrier coatings. The oxygen permeability was measured at different humidity levels, and the material properties were characterized under the same conditions: polymer crystallinity, kaolin concentration, and kaolin orientation were all evaluated. The experimental results revealed that the water plasticizes the PVOH material of the coatings, and the presence of kaolin filler is unable to affect such behavior significantly. The PVOH crystallinity was affected drastically by the humidity, as water melts polymer crystallites, which is a reversible process under removal of water. The permeability data were analyzed using a thermodynamicbased model able to account for the water effect on both the solubility of the gas and the diffusivity coefficients in the polymer and composite. The results showed good agreement between the model’s predictions and the experimental data in terms of the overall permeability of the material.

Place, publisher, year, edition, pages
Springer, 2017
Keywords
Mass transport, Permeability, Modeling, Barrier coating, Moisture, Kaolin, PVOH
National Category
Polymer Technologies Composite Science and Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-47462 (URN)10.1007/s11998-017-9937-2 (DOI)000422975500012 ()
Funder
Knowledge Foundation, 20100268Stora Enso
Available from: 2016-12-13 Created: 2016-12-07 Last updated: 2022-03-30Bibliographically approved
5. An economic-environmental analysis of selected barrier coating materials used in packaging food products: A Swedish case study
Open this publication in new window or tab >>An economic-environmental analysis of selected barrier coating materials used in packaging food products: A Swedish case study
2018 (English)In: Environment, Development and Sustainability, ISSN 1387-585X, E-ISSN 1573-2975, Vol. 20, no 4, p. 1483-1497Article in journal (Refereed) Published
Abstract [en]

The purpose of a barrier coating in food packaging is primarily to increase the shelf life of the foodstuff contained within the packaging, preserve its colour, odour, taste and quality, and thereby reduce food wastage (both at retail outlets and households). While most publications hitherto have compared packaging and barrier-coating materials on the basis of their environmental impacts alone, this paper adopts a more holistic approach by factoring in the economic aspect as well. Four barrier material alternatives—starch, polyethylene, EVOH + kaolin and latex + kaolin are analysed. Two well-defined end-of-life handling scenarios, relevant to Sweden, are: one in which everything except starch is recycled, with starch being composted, and the other in which everything is incinerated. Among the several environmental impact categories which can be analysed, this paper considers only global warming. Two approaches are tested to combine the economic and environmental aspects—normalisation, weighting and aggregating on the one hand, and using the carbon tax to internalise the externality caused by GHG emissions on the other. For the set of weighting factors obtained thanks to a survey conducted by the authors (40.6% for environmental and 59.4% for economic), starch emerges as the most sustainable alternative, followed by polyethylene for both the end-of-life handling scenarios. This tallies with the result obtained by using the carbon tax for internalisation of the externality. The case study, methodology and results presented in this paper, will hopefully be a springboard for more detailed studies of this nature, under the umbrella of sustainability.

Place, publisher, year, edition, pages
Dordrecht: Springer, 2018
Keywords
Barrier coatings, Starch, Kaolin, Latex, EVOH Polyethylene, Environmental LCA, Sustainability, Economic
National Category
Polymer Technologies Environmental Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-47463 (URN)10.1007/s10668-017-9948-2 (DOI)000437438300003 ()
Available from: 2016-12-13 Created: 2016-12-07 Last updated: 2022-05-30Bibliographically approved

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