| 1. |
- Eichhorn, S. J., et al.
(författare)
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Review : current international research into cellulose nanofibres and nanocomposites
- 2010
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Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 45:1, s. 1-33
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Forskningsöversikt (refereegranskat)abstract
- This paper provides an overview of recent progress made in the area of cellulose nanofibre-based nanocomposites. An introduction into the methods used to isolate cellulose nanofibres (nanowhiskers, nanofibrils) is given, with details of their structure. Following this, the article is split into sections dealing with processing and characterisation of cellulose nanocomposites and new developments in the area, with particular emphasis on applications. The types of cellulose nanofibres covered are those extracted from plants by acid hydrolysis (nanowhiskers), mechanical treatment and those that occur naturally (tunicate nanowhiskers) or under culturing conditions (bacterial cellulose nanofibrils). Research highlighted in the article are the use of cellulose nanowhiskers for shape memory nanocomposites, analysis of the interfacial properties of cellulose nanowhisker and nanofibril-based composites using Raman spectroscopy, switchable interfaces that mimic sea cucumbers, polymerisation from the surface of cellulose nanowhiskers by atom transfer radical polymerisation and ring opening polymerisation, and methods to analyse the dispersion of nanowhiskers. The applications and new advances covered in this review are the use of cellulose nanofibres to reinforce adhesives, to make optically transparent paper for electronic displays, to create DNA-hybrid materials, to generate hierarchical composites and for use in foams, aerogels and starch nanocomposites and the use of all-cellulose nanocomposites for enhanced coupling between matrix and fibre. A comprehensive coverage of the literature is given and some suggestions on where the field is likely to advance in the future are discussed.
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| 2. |
- Harvey, B. P., et al.
(författare)
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Evolution of marine organisms under climate change at different levels of biological organisation
- 2014
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 6:11, s. 3545-3574
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Tidskriftsartikel (refereegranskat)abstract
- Research to date has suggested that both individual marine species and ecologicalprocesses are expected to exhibit diverse responses to the environmental effects of climatechange. Evolutionary responses can occur on rapid (ecological) timescales, and yet studiestypically do not consider the role that adaptive evolution will play in modulating biologicalresponses to climate change. Investigations into such responses have typically been focusedat particular biological levels (e.g., cellular, population, community), often lackinginteractions among levels. Since all levels of biological organisation are sensitive to globalclimate change, there is a need to elucidate how different processes and hierarchicalinteractions will influence species fitness. Therefore, predicting the responses ofcommunities and populations to global change will require multidisciplinary efforts acrossmultiple levels of hierarchy, from the genetic and cellular to communities and ecosystems.Eventually, this may allow us to establish the role that acclimatisation and adaptation willplay in determining marine community structures in future scenarios.
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| 3. |
- Wik, V. M., et al.
(författare)
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Castor Oil-based Polyurethanes Containing Cellulose Nanocrystals
- 2011
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Ingår i: Polymer Engineering and Science. - : Wiley. - 0032-3888 .- 1548-2634. ; 51:7, s. 1389-1396
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Tidskriftsartikel (refereegranskat)abstract
- Partially foamed and nanocellulose-reinforced polyurethanes (PU) based on castor oil (CO) were prepared and their different properties were measured and related to their structures. A castor oil-based polyol (COPO) was obtained by alcoholysis of CO with triethanolamine. The COPO was used in the preparation of partially foamed and solid PU. Cellulose nanofibrils (NC) in the range of the rheological percolation content were incorporated to the materials and the final mechanical properties of these nanocomposites were analyzed. The incorporated NC considerably affected the rheology of the suspensions, which presented solid-like behavior under frequency sweep tests with the addition of only 0.5 wt% of NC. By increasing the NC concentration the dispersion becomes increasingly difficult. The properties of the solid PU were also affected by the incorporation of NC and a significant increase of the tensile modulus was observed for the 0.5 wt% NC composite, compared to the unfilled solid PU. This behavior was associated to the incorporation of the rigid particle reinforcement and the interfacial bonding. As expected, the partially foamed PU showed lower modulus than the corresponding solid PU.
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| 4. |
- Nunez, A. J., et al.
(författare)
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Toughening of wood particle composites - Effects of sisal fibers
- 2006
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 101:3, s. 1982-1987
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Tidskriftsartikel (refereegranskat)abstract
- Sisal fibers were added to wood particle composites to enhance their toughness. The selected matrix was a commercial styrene diluted unsaturated polyester thermoset resin. Fracture tests were carried out using single-edge notched beam geometries. Stiffness, strength, critical stress intensity factor K-IQ, and work of fracture W-f of notched specimens were determined. The incorporation of sisal fibers into wood particle composites significantly changed the fracture mode of the resulting hybrid composite. For the neat matrix and the wood particle composites, once the maximum load was reached, the crack propagated in a catastrophic way. For hybrid composites, fiber bridging and pull-out were the mechanisms causing increased crack growth resistance. Addition of a 7% wt of sisal fibers almost doubled the K-IQ value of a composite containing 12% wt of woodflour. Moreover, the W-f increased almost 10-fold, for the same sample. In general, the two composite toughness parameters K-IQ and W-f increased when the fraction of sisal fibers was increased.
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