| 1. |
- Ran, Ylva, et al.
(författare)
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Environmental assessment of diets: overview and guidance on indicator choice
- 2024
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Ingår i: The Lancet Planetary Health. - : Elsevier BV. - 2542-5196. ; 8:3, s. e172-e187
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Forskningsöversikt (refereegranskat)abstract
- Comprehensive but interpretable assessment of the environmental performance of diets involves choosing a set of appropriate indicators. Current knowledge and data gaps on the origin of dietary foodstuffs restrict use of indicators relying on site-specific information. This Personal View summarises commonly used indicators for assessing the environmental performance of diets, briefly outlines their benefits and drawbacks, and provides recommendations on indicator choices for actors across multiple fields involved in activities that include the environmental assessment of diets. We then provide recommendations on indicator choices for actors across multiple fields involved in activities that use environmental assessments, such as health and nutrition experts, policy makers, decision makers, and private-sector and public-sector sustainability officers. We recommend that environmental assessment of diets should include indicators for at least the five following areas: climate change, biosphere integrity, blue water consumption, novel entities, and impacts on natural resources (especially wild fish stocks), to capture important environmental trade-offs. If more indicators can be handled in the assessment, indicators to capture impacts related to land use quantity and quality and green water consumption should be used. For ambitious assessments, indicators related to biogeochemical flows, stratospheric ozone depletion, and energy use can be added.
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| 2. |
- Börjesson, Mikaela, 1987, et al.
(författare)
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Arabinoxylan and Nanocellulose from a Kilogram-scale Extraction of Barley Husk
- 2019
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Ingår i: BioResources. - : BioResources. - 1930-2126 .- 1930-2126. ; 13:3, s. 6201-6220
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Tidskriftsartikel (refereegranskat)abstract
- Processes of extracting hemicellulose from annual plants usually neglect the cellulose fraction. This study explored the possibility of obtaining both a hemicellulose and a cellulose fraction of sufficient quality for further use, with barley husks used as the raw material. An alkaline extraction was used to isolate the biopolymers by a process in which sodium dithionite replaced the traditional sodium borohydride as the reducing agent. The cellulose fraction was successfully transformed into nanocellulose by sulfuric acid hydrolysis, and the obtained hemicellulose (i.e., arabinoxylan) displayed carbohydrate composition characteristics similar to those previously reported in the literature for processes of extracting hemicellulose from barley husks. Using this methodology, both the cellulose and hemicellulose can be isolated in high quantities of dry material and used for transformation into new bio-based materials.
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| 3. |
- Härdelin, Linda, 1977, et al.
(författare)
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Hemicellulose foam
- 2014
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Ingår i: Proc Materials for Tomorrow. ; , s. Nr 24-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Karlsson, Kristina, 1988, et al.
(författare)
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Chain-Length Shortening of Methyl Ethyl Hydroxyethyl Cellulose : An Evaluation of the Material Properties and Effect on Foaming Ability
- 2018
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Ingår i: Journal of Polymers and the Environment. - : Springer Science and Business Media LLC. - 1566-2543 .- 1572-8919. ; 26:11, s. 4211-4220
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Tidskriftsartikel (refereegranskat)abstract
- During the past century, plastics have become a natural element in our every-day life. Lately however, an awareness about the fossil origin and often non-degradable nature of many plastics is rising. This has resulted in the emergence of some bio-based and/or biodegradable plastics, often produced from renewable resources. One possible candidate for bioplastics production could be found in cellulose. This paper aims at contributing information regarding a cellulose derivative, which could possibly be used in foamed plastics applications. Therefore, the reduction of the chain-length of a methyl ethyl hydroxyethyl cellulose (MEHEC), assessed by size exclusion chromatography, and the effect of chain-length on the foaming behaviour were studied. The foaming was accomplished with a hot-mould technique using aqueous polymer solutions. The generated steam was here used as the blowing agent and important parameters were polymer concentration and solution viscosity. The density of the produced foams was assessed and was in some cases comparable to that of commodity foams. It was found that reducing the chain-length enabled an increase of the initial polymer concentration for the foaming process. This is believed to be beneficial for creating more structurally stable foams of this type.
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| 5. |
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| 6. |
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| 7. |
- Karlsson, Kristina, 1988, et al.
(författare)
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Extrusion Parameters for Foaming of a β-Glucan Concentrate
- 2019
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Ingår i: Journal of Polymers and the Environment. - : Springer Science and Business Media LLC. - 1566-2543 .- 1572-8919. ; 27:6, s. 1167-1177
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Tidskriftsartikel (refereegranskat)abstract
- Plastics is a group of materials commonly encountered on a daily basis by many people. They have enabled rapid, low-cost manufacturing of products with complicated geometries and have contributed to the weight reduction of heavy components, especially when produced into a foamed structure. Despite the many advantages of plastics, some drawbacks such as the often fossil-based raw-material and the extensive littering of the material in nature, where it is not degraded for a very long time, needs to be dealt with. One way to address at least one of the issues could be to use polymers from nature instead of fossil-based ones. Here, a β-glucan concentrate originating from barley was investigated. The concentrate was processed into a foam by hot-melt extrusion, and the processing window was established. The effect of different blowing agents was also investigated. Water or a combination of water and sodium bicarbonate were used as blowing agents, the latter apparently giving a more uniform pore structure. The porous structure of the foamed materials was characterized mainly by using a combination of confocal laser scanning microscope and image analysis. The density of the samples was estimated and found to be in a similar range as some polyurethane foams. A set of 3D parameters were also quantified on two selected samples using X-ray microtomography in combination with image analysis, where it was indicated that the porous structure had a pre-determined direction, which followed the direction of the extrusion process. © 2019, The Author(s).
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| 8. |
- Karlsson, Kristina, 1988, et al.
(författare)
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Flow behaviour and microstructure of a beta-glucan concentrate
- 2018
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Ingår i: Journal of Polymers and the Environment. - : Springer Science and Business Media LLC. - 1572-8919 .- 1566-2543. ; 26:8, s. 3352-3361
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Tidskriftsartikel (refereegranskat)abstract
- The extensional viscosity is an important rheological characteristic of polymer melts. It is however not as frequently reported on as the shear viscosity. The extensional viscosity is of special interest when considering polymeric materials for foaming and film blowing processes. Here, the extensional (and shear) viscosity along with the melt strength and the tensile properties of the corresponding solid film of a β-glucan concentrate are reported on. A capillary viscometer equipped with a hyperbolic die, yielding a contraction flow, was used to assess the extensional viscosity of the aqueous β-glucan compound at room temperature and at elevated temperatures (110 and 130 °C). In general, the extensional viscosity as well as the shear viscosity decreased with increasing deformation rate. The influence of two different amounts of added water (40 and 50%) was also examined. As expected, both types of viscosities decreased with increasing temperature. It is suggested that gelatinization of the starch fraction in the concentrate at 110 and 130 °C contributes to temperature dependence of the viscosity. To some extent, this is supported by light microscopy and confocal scanning laser microscopy studies of the microstructure of the materials. The results reported here indicate that the β-glucan concentrate might, after some modifications, be used as a complement to fossil-based polymers and processed by conventional manufacturing techniques.
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| 9. |
- Karlsson, Kristina, 1988, et al.
(författare)
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Foaming behavior of water-soluble cellulose derivatives : hydroxypropyl methylcellulose and ethyl hydroxyethyl cellulose
- 2015
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Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 22:4, s. 2651-2664
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Tidskriftsartikel (refereegranskat)abstract
- Hydroxypropyl methylcellulose and ethyl hydroxyethyl cellulose could be interesting candidates for production of lightweight, foamed packaging material originating from non-fossil, renewable resources. The foaming ability of nine different grades of the two cellulose derivatives, using water as the blowing agent, was investigated using a hot-mold process. The foaming process was studied by evaluating the water loss during the heating, both in a real-time experiment and by thermal gravimetric analysis. Further, the development of the rheological properties of the derivative-water mixtures during a simulated foaming process was assessed using dynamical mechanical thermal analysis and viscosity measurements. Five of the studied derivatives showed promising properties for hot-mold foaming and the final foams were characterized with regard to their apparent density. It was concluded that the foamability of these systems seems to require a rather careful tailoring of the viscoelastic properties in relation to the water content in order to ensure that a network structure is built up and expanded during the water evaporation.
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| 10. |
- Karlsson, Kristina, 1988
(författare)
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Foaming of cellulose derivatives and hemicellulose-containing materials
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fossil-based polymeric foams are important materials due to their good mechanical properties relative their low density, the low price and the possibility for large-scale production. They are widely used in cushioning, absorbing and insulation applications. There are however a few disadvantages with these foamed products. The raw-material originates from a non-renewable resource. In the foaming process some possible less environmentally friendly additives/blowing agents are used. Also, the relatively low price of these foamed articles makes them ideal for single-use packaging and, unfortunately, they often end up in nature where the slow degradation will ensure that they stay for a long time, causing problems for marine living and other species. One possible way to solve at least some of the issues relating to fossil-based foamed products would be to use a renewable, non-fossil, raw material. There are several polymers of a non-fossil origin which could serve a primary material for foams and in this thesis two different types of cellulose derivatives (hydroxypropyl methylcellulose (HPMC) and ethyl hydroxyethyl cellulose (EHEC)) as well as a number of different hemicelluloses (xylan, arabinoxylan (AX), β-glucan concentrate and galactoglucomannan (GGM)) were studied as possible and interesting candidates. The foaming ability of some different grades of the two cellulose derivatives, xylan, AX and GGM, was initially evaluated using a hot-mould process with water as the only blowing agent and plasticiser. A simulated foaming process was assessed using dynamical mechanical thermal analysis (DMTA) for HPMC and the rheological properties of the polymer-water mixtures were determined. Three grades of the HPMC derivatives were evaluated in a small-scale batch extrusion experiment using a capillary viscometer. Also, the β-glucan concentrate (mixed with water) was foamed in the capillary viscometer and its shear and extensional viscosities were evaluated. The results pointed towards the existence of a possible processing window for foaming and extrusion experiments were therefore performed with the HPMC and the β-glucan polymers. For HPMC, water was the only added plasticiser and blowing agent and for the β-glucan concentrate also sodium bicarbonate and citric acid were used along with the water. The final foams from both foaming techniques were characterised with regard to their apparent density and foam structure. In conclusion, cellulose derivatives and hemicelluloses could be suitable candidates for production of lightweight, foamed material originating from non-fossil, renewable resources.
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