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- Azizi Samir, M. A. S., et al.
(författare)
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High performance nanocomposite polymer electrolytes
- 2006
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Ingår i: Composite interfaces (Print). - : Informa UK Limited. - 0927-6440 .- 1568-5543. ; 13:4-6, s. 545-559
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Tidskriftsartikel (refereegranskat)abstract
- Solid lithium-conducting nanocomposite polymer electrolytes based on poly(oxyethylene) (POE) were prepared using high aspect ratio cellulosic whiskers and lithium imide salt, LiTFSI. The cellulosic whiskers were extracted from tunicate - a sea animal - and consisted of slender parallelepiped rods that have an average length around 1 μm and a width close to 15 nm. High performance nanocomposite electrolytes were obtained. The filler provided a high reinforcing effect, despite the favorable cellulose/POE interactions that were expected to decrease the possibility of interwhisker connection and formation of a percolating cellulosic network, while a high level of ionic conductivity was retained with respect to unfilled polymer electrolytes. Cross-linking and plasticizing of the matrix as well as preparation of the composites from an organic medium were also investigated.
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| 2. |
- Azizi Samir, M. A. S., et al.
(författare)
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Review of recent research into cellulosic whiskers, their properties and their application in nanocomposite field
- 2005
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 6:2, s. 612-626
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Tidskriftsartikel (refereegranskat)abstract
- There are numerous examples where animals or plants synthesize extracellular high-performance skeletal biocomposites consisting of a matrix reinforced by fibrous biopolymers. Cellulose, the world's most abundant natural, renewable, biodegradable polymer, is a classical example of these reinforcing elements, which occur as whiskerlike microfibrils that are biosynthesized and deposited in a continuous fashion. In many cases, this mode of biogenesis leads to crystalline microfibrils that are almost defect-free, with the consequence of axial physical properties approaching those of perfect crystals. This quite "primitive" polymer can be used to create high performance nanocomposites presenting outstanding properties. This reinforcing capability results from the intrinsic chemical nature of cellulose and from its hierarchical structure. Aqueous suspensions of cellulose crystallites can be prepared by acid hydrolysis of cellulose. The object of this treatment is to dissolve away regions of low lateral order so that the water-insoluble, highly crystalline residue may be converted into a stable suspension by subsequent vigorous mechanical shearing action. During the past decade, many works have been devoted to mimic biocomposites by blending cellulose whiskers from different sources with polymer matrixes.
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| 3. |
- Mathew, Aji P., et al.
(författare)
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Mechanical properties of nanocomposites from sorbitol plasticized starch and tunicin whiskers
- 2008
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 109:6, s. 4065-4074
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Tidskriftsartikel (refereegranskat)abstract
- Nanocomposite materials were obtained using sorbitol plasticized waxy maize starch as matrix and tunicin whiskers as the reinforcement. The effect of filler load (0-25 wt % whiskers) and the relative humidity levels (0-98%) on the mechanical behavior of the films are discussed for linear and nonlinear deformation. The performance of the films is explained, based on the morphology and structural behavior of the composite materials (Mathew and Dufresne, Biomacromolecules 2002, 3, 609). The nanocomposites exhibit good mechanical strength due to the strong interaction between tunicin whiskers, matrix, plasticizer (sorbitol), and water, and due to the ability of the cellulose filler to form a rigid three-dimensional network. The evolution of Tg as a function of relative humidity level and filler load is studied in detail. A decrease in crystallinity of the amylopectin phase is observed at high filler loads, due to the resistance to chain rearrangement imposed by the whiskers. The mechanical strength increased proportionally with filler loads, showing an effective stress transfer from the matrix to the whiskers. An even distribution of whiskers (as determined by SEM) and plasticizer in the matrix contributes to the mechanical performance. The mechanical properties of the nanocomposites showed a strong dependence on relative humidity conditions.
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