| 1. |
- Eyholzer, Christian, et al.
(författare)
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Biocomposite hydrogels with carboxymethylated, nanofibrillated cellulose powder for replacement of the nucleus pulposus
- 2011
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 12:5, s. 1419-1427
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Tidskriftsartikel (refereegranskat)abstract
- Biocomposite hydrogels with carboxymethylated, nanofibrillated cellulose (c-NFC) powder were prepared by UV polymerization of N-vinyl-2-pyrrolidone with Tween 20 trimethacrylate as a crosslinking agent for replacement of the native, human nucleus pulposus (NP) in intervertebral discs. The swelling ratios and the moduli of elasticity in compression of neat and biocomposite hydrogels were evaluated in dependence of c-NFC concentration (ranging from 0 to 1.6% v/v) and degree of substitution (DS, ranging from 0 to 0.23). The viscoelastic properties in shear and the material relaxation behavior in compression were measured for neat and biocomposite hydrogels containing 0.4% v/v of fibrils (DS ranging from 0 to 0.23) and their morphologies were characterized by cryo-scanning electron microscopy (cryo-SEM). The obtained results show that the biocomposite hydrogels can successfully mimic the mechanical and swelling behavior of the NP. In addition, the presence of the c-NFC show lower strain values after cyclic compression tests and consequently create improved material relaxation properties, compared to neat hydrogels. Among the tested samples, the biocomposite hydrogel containing 0.4% v/v of c-NFC with a DS of 0.17 shows the closest behavior to native NP. Further investigation should focus on evaluation and improvement of the long-term relaxation behavior.
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| 2. |
- Jin, H., et al.
(författare)
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Effects of different drying methods on textural properties of nanocellulose aerogels
- 2009
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Ingår i: ICCM International Conferences on Composite Materials.
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Konferensbidrag (refereegranskat)abstract
- There is increasing research interest in nanocellulose aerogels because they have low density, hierarchical structure and they are biodegradable and biocompatible. Typically, aerogels are made by supercritical drying, freeze drying and vacuum drying. This work will report the effects that different drying methods have on textural properties of aerogels.
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| 3. |
- Neagu, R. C., et al.
(författare)
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Processing and mechanical properties of novel wood fibre composites foams
- 2009
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Ingår i: ICCM International Conferences on Composite Materials.
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Konferensbidrag (refereegranskat)abstract
- Wood fibre reinforced polylactic acid (PLA) composite foams have been successfully produced using supercritical carbon dioxide. A significant increase of specific properties, both stiffness and strength, was achieved by adding 5-10 wt% wood fibres. The experimental stiffness was comparable with a superposed micromechanical model for a three phase fibre reinforced foam. These first results on the integration of wood fibres into cellular PLA polymer are very encouraging.
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| 4. |
- Plummer, C. J. G., et al.
(författare)
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Influence of processing routes on morphology and low strain stiffness of polymer/nanofibrillated cellulose composites
- 2015
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Ingår i: Plastics, rubber and composites. - 1465-8011 .- 1743-2898. ; 44:3, s. 81-86
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Tidskriftsartikel (refereegranskat)abstract
- The morphology of polymer/nanofibrillated cellulose (NFC) composite sheets produced using different techniques and its influence on low strain stiffness were assessed by optical and transmission electron microscopy. Solvent processing led to relatively homogeneous NFC dispersions and significant reinforcement of the in-plane Young's modulus. The continuous cellular networks obtained by wet comingling of polylactide powder or latex with NFC also provided efficient and essentially scale independent reinforcement, in spite of the extensive agglomeration of the NFC. However, the irreversible nature of these networks is incompatible with low pressure thermoplastic processing routes such as physical foaming, and while they may be broken up by e.g. extrusion, this led to substantial loss in reinforcement, particularly at temperatures above the glass transition temperature of the matrix, consistent with the observation of isolated low aspect ratio NFC aggregates in the extruded specimens.
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| 5. |
- Plummer, C. J. G., et al.
(författare)
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Influence of processing routes on the morphology and properties of polymer/nanofibrillated cellulose composites
- 2014
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Ingår i: 16th European Conference on Composite Materials, ECCM 2014. - 9780000000002
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Konferensbidrag (refereegranskat)abstract
- The morphology of polymer/nanofibrillated cellulose (NFC) composite sheets produced using different techniques and its influence on low strain stiffness were assessed by optical and transmission electron microscopy. Solvent processing led to relatively homogeneous NFC dispersions and significant reinforcement of the in-plane Young's modulus. The continuous cellular networks obtained by wet-comingling of PLA powder or latex with NFC also provided efficient and essentially scale-independent reinforcement, in spite of the extensive agglomeration of the NFC. However, the irreversible nature of these networks is incompatible with low pressure thermoplastic processing routes such as physical foaming, and while they may be broken up by e.g. extrusion, this led to substantial loss in reinforcement, particularly above Tg, consistent with the observation of isolated low aspect ratio NFC aggregates in the extruded specimens.
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