| 1. |
- Jönbrink, Anna Karin, et al.
(författare)
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Create Competitiveness In A Sustainable Society : - Use Ecodesign, In Cooperation
- 2011
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Ingår i: Design for Innovative Value Towards a Sustainable Society. - Dordrecht : Springer Science+Business Media B.V.. ; , s. 430-433
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Konferensbidrag (refereegranskat)abstract
- This paper will describe a new methodology for the use of Ecodesign, where various competences are combined to obtain high quality results. The competences needed are: Environmental experts, who can evaluate the environmental performance of a product or service through Life Cycle Assessment, LCA, material- and process experts for the materials and processes in the targeted product or service, experts of the final product or service who can provide high quality data for the LCA. This cross functional team can develop new products or services, with high performance combined with low environmental impact, applying ecodesign when cooperating closely. Using this methodology is a feasible way to obtain improved competitiveness for the industry in a sustainable society.
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| 2. |
- Andersons, J., et al.
(författare)
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Scale effect of the tensile strength of flax-fabric-reinforced polymer composites
- 2011
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Ingår i: Journal of reinforced plastics and composites (Print). - : SAGE Publications. - 0731-6844 .- 1530-7964. ; 30:23, s. 1969-1974
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Tidskriftsartikel (refereegranskat)abstract
- The development of UD natural fiber composites, considered for application as structural materials, necessitates evaluation of the scale effect of their strength. Alignment of the fibers in flax bast fiber composites can be achieved by employing textile reinforcement, such as yarns and fabrics. Cutting specimens for mechanical tests out of such textile-reinforced composite plates results in a complex non-uniform reinforcement structure at their edges, which may affect the strength of specimens. Scale effect of the tensile strength in the fiber direction of flax-fabric-reinforced composites is studied in the current work. A model accounting for both volume and edge effect of the specimens on their tensile strength is proposed. © The Author(s) 2011.
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| 3. |
- Gong, Guan, et al.
(författare)
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Development of polyethylene/nanoclay masterbatch for use in wood-plastic composites
- 2013
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Ingår i: Plastics, rubber and composites. - 1465-8011 .- 1743-2898. ; 42:4, s. 167-175
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Konferensbidrag (refereegranskat)abstract
- In this work, organoclay reinforced high density polyethylene (HDPE) nanocomposites were prepared at laboratory scale using a batch mixer. Processing conditions, maleic anhydride modified polyethylene (MAPE) type and MAPE/clay weight ratio were optimised. The microstructure of the resultant nanocomposites was analysed by X-ray diffraction and melt rheology tests, and flexural properties and thermal stability were evaluated. Three types of MAPEs with different melt flow indices (MFI) and maleic anhydride contents all improved the interaction between HDPE and clay and promoted clay dispersion. Nanocomposites where the MAPE with MFI most similar to HDPE was used showed the best exfoliation of clay and the strongest HDPE/clay interface. Mechanical properties were slightly improved, while thermal stability was distinctly enhanced in these HDPE nanocomposites compared with neat HDPE and HDPE nanocomposite without MAPE. The prepared HDPE nanocomposites show the potential to improve the thermal stability of wood-plastic composites for structural applications. © 2013 Institute of Materials, Minerals and Mining.
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| 4. |
- Gong, Guan, et al.
(författare)
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Enhanced thermal stability and flame retarding properties of recycled polyethylene based wood composites via addition of polyethylene/nanoclay masterbatch
- 2013
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Ingår i: Plastics, rubber and composites. - 1465-8011 .- 1743-2898. ; 42:6, s. 244-255
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Tidskriftsartikel (refereegranskat)abstract
- Barrier and mechanical properties of wood powder composites based on recycled polyethylene (RPE) were modified using a commercial nanoclay masterbatch. X-ray diffraction, dynamic rheology and thermogravimetric analysis measurements showed that nanoclay from the selected masterbatch was well dispersed and formed a percolation network in both virgin and RPEs. The resulting nanocomposites promoted the thermal stability of matrix significantly. Modification efficiency of nanoclay, however, was evidently influenced by the type of matrix, where the strongest effect was achieved in a low viscosity virgin high density PE. The masterbatch was incorporated into an industrial formula designed extrusion quality RPE/wood flour composite. Processing procedures, mainly compounding cycles, and material composition, mainly clay content and type of coupling agent, were optimised. Two extrusion cycles led to higher uniformity of resulting composites than one cycle. Addition of a coupling agent, which has medium viscosity and plenty functional groups, led to enhanced tensile strength. The twice compounded composites were well stiffened and strengthened via combination of 6 wt-% clay and medium viscosity coupling agent. All composites without the addition of nanoclay burned faster after ignition and dripped much earlier and more compared to the composites containing nanoclay even with as small amount as 3 wt-% and being compounded once. The material with 6 wt-% clay showed the best sample integrity and burned slowest of all the tested composites. Furthermore, no dripping during combustion was seen for this material. This study shows that the incorporation of nanoclay using the selected masterbatch can effectively improve the flame retarding properties of RPE based wood composites.
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| 5. |
- Joffe, Roberts, et al.
(författare)
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Suitability of man made cellulose fibers as reinforcement for bio-based polymer composites
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- It has been demonstrated that natural fibers, such as flax and hemp for example, have mechanical properties competitive to those of glass fibers. This makes such fibers very goodpotential reinforcement for polymer composites. However, there are certain difficulties to utilize those properties on the extent that composites based on these fibers become alsocompetitive with synthetic materials in terms of mechanical performance. One of the problems is poor adhesion between matrix and fibers, which can be improved by additionalfiber treatment or by use of more compatible polymers (for example bio-based resins).Another issue is related to the length or the fibers and their orientation. Normally natural fibers are fairly short and thus it is difficult to maintain their pre-define orientation in thecomposite. Finally, maybe one of the biggest drawbacks of natural fibers is variability of their properties: quality of fibers will differ depending on location of growth and time of harvest.Moreover, large variability of properties can be observed even within the same batch of fibers. Sometimes these disadvantages can overshadow the main advantage of these materials– they are environmentally friendlier than synthetic materials and they are sustainable.Due to these concerns, the other type of reinforcement with plant origin (and high cellulose content, similar to flax and hemp fibers) has recently caught an attention as alternativereinforcement for bio-based composites - regenerated cellulose fibers. Although these are manmade fibers, they are made out of the natural polymer directly in contrary to the fibersmade out materials with fossil origin. These fibers are continuous and it is easy to arrange them into fabrics with stable orientation and geometry. These fibers have been discovered for more than a century ago but until now they have not been seriously considered for use in high performance polymer composites. At present the main application of these fibers is within textile industry and in tire processing.The current study focuses on characterization of regenerated cellulose fibers (namely Cordenka fibers) in order to evaluate them as perspective reinforcement for bio-based polymer composites. General mechanical performance, statistical strength distribution as well as viscoelastic behaviour of the Cordenka fibers are presented. Influence of moisture andtemperature on mechanical properties is also examined. Suitability of regenerated cellulose fibers as reinforcement for bio-based polymer composites is discussed.
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| 6. |
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| 7. |
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| 8. |
- Mannberg, Peter, et al.
(författare)
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Service life assessment and moisture influence on bio-based composites
- 2014
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Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 49:15, s. 5265-5270
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Tidskriftsartikel (refereegranskat)abstract
- A race towards a more sustainable society is going on worldwide and decreasing dependence on fossil resources in energy and transport sectors is main goals. One path to decreased oil usage is development of lightweight materials from renewable resources like bio-based composites. However these new bio-based materials have not only to compete in mechanical performance, they also have to restrain environmental loads like moisture and temperature over time. In this study two bio-based composites have been compared to an oil-based composite in terms of long-term properties and water absorption behaviour. The long-term behaviour is determined by dynamic mechanical thermal analysis, DMTA, and time temperature superposition, TTSP. The water uptake is determined by submersion of specimens into water and tracking their weight change over time. The moisture influence is characterised in form of water uptake and change in the master curves created by TTSP procedure. The results show that there is a significant difference in long-term performance between the bio-based and oil-based composites. It is realized that the bio-based composites can be a good alternative for some applications especially when taking their eco-friendly nature into account.
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| 9. |
- Mannberg, Peter, et al.
(författare)
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Service life assessment and moisture influence on bio-based thermosetting resins
- 2014
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Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 49:10, s. 3687-3693
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Tidskriftsartikel (refereegranskat)abstract
- In this study, three different types of bio-based resins are compared to a conventional oil-based epoxy in terms of moisture uptake, long-term properties and its influence of moisture and glass transition temperature, T g. Moisture uptake is determined by means of gravimetric method, time temperature superposition (TTSP), and T g data obtained in dynamic mechanical thermal analysis (DMTA). Moisture uptake show Fickian diffuison behavour for all resins, saturation level and diffusion coefficient however differ. The long-term properties is characterised by creep compliance master curves created by means of TTSP. The examined bio-based resins are compatible to the reference epoxy in term of stability up to 3–10 years. Comparison between master curves for virgin, wet, and dried material show that moisture present in the specimen increases creep rate, and that some of this increase remains after drying of samples. T g measurements show that moisture inside the specimen decreases T g; this is anticipated because of the plasticizing effect of water. The overall conclusions are that the bio-based resins of polyester, and epoxy type are comparable in performance with oil-based epoxy, LY556 and they can be used to develop high-performance composites.
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| 10. |
- Mannberg, Peter, et al.
(författare)
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Service life assessment and moisture influence on composites from renewable feedstock
- 2012
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Ingår i: Proceedings of Mechanics of Composite Materials XVII International Conference.
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Konferensbidrag (refereegranskat)abstract
- Composite materials are an important and growing material group in a large number of industries such as aeronautics, marine, automotive, energy production and infrastructure. The most common composite materials is manufactured from fibres such as glass fibres and carbon fibres together with oil based resins i.e. polyester, vinyl ester and epoxy. An increasing use calls for alternative environmental friendly, biobased, constituents. The new biobased materials have not only to compete in mechanical properties but it also has to restrain environmental loads like moisture and temperature over time. In the present work are predictions of the long term properties of biobased resins made. The work also presents the influence of moisture, comparison with creep test data and comparison with oil based resin. The long term property prediction is made by using dynamic mechanical thermal analysis, DMTA, measurements and time temperature superposition, TTSP, [1,2]. The procedure is to make DMTA measurements in 3p-bening mode of the storage modulus at different frequencies at increasing temperature. The method used in this case was to measure the modulus at 0.1, 0.3, 1, 3 and 10 Hz at temperatures 25 – 175°C with 5°C intervals. The frequencies where then transformed to time by Eq. (1) below t=2/πω (1)where ω is the frequency. 25°C were chosen as reference temperature where as all other curves where shifted horizontally creating a continuous master curve. The modulus time master curve was then inverted creating creep compliance time master curve, this curve is compared to creep test. The moisture behaviour is characterised in form of water uptake, change in glass transition temperature, Tg, and change in dynamic response. The water uptake is determined by submersion into water and tracking the weight change over time. The glass transition temperature is determined in DMTA by conducting a temperature sweep at constant frequency. The change in Tg is used as a knock down factor and a vertical shift of the master curve. An attempt to determine the dynamic response of wet samples has also been made with the insight that higher temperatures will dry the sample during testing leading to a non homogenous moisture distribution within the sample. The results from the study show on differences between TTSP and creep data, it also shows the differences between different biobased resins and a comparison to oil based epoxy. REFERENCES1. Christensen R.M., “Theory of viscoelasticity, an introduction” 2nd edition, Academic Press, 1982.2. Ward I.M. and Hadley D.W., “An Introduction to the mechanical properties of solid polymers” 1st edition, John Wiley & Sons, 1993.
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