Change search
ReferencesLink to record
Permanent link

Direct link
Biomimetic Foams of High Mechanical Performance Based on Nanostructured Cell Walls Reinforced by Native Cellulose Nanofibrils
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.ORCID iD: 0000-0001-5818-2378
2008 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 20, no 7, 1263-1269 p.Article in journal (Refereed) Published
Abstract [en]

 A bioinspired foam in which cellulose nanofibrils are used to reinforce cell walls (ca. 3 mu m) is presented. The nanocomposite foams are prepared by a lyophilization technique and show composite structure at the cell-wall scale. The nanocellulosic network shows remarkable mechanical performance, expressed in much-improved modulus and yield strength compared with the neat starch foam.

Place, publisher, year, edition, pages
Weinheim: Wiley-VCH Verlag GmbH , 2008. Vol. 20, no 7, 1263-1269 p.
Keyword [en]
ABS resins, Biodegradable polymers, Biomimetics, Cellulose, Cellulose derivatives, Dewatering, Hydrolysis, Metallic matrix composites, Microbial fuel cells, Nanocomposites, Nanostructured materials, Polymer matrix composites, Polysaccharides, Reinforcement, Water content
National Category
Engineering and Technology
URN: urn:nbn:se:kth:diva-9653DOI: 10.1002/adma.200701215ISI: 000255348900007ScopusID: 2-s2.0-54949096154OAI: diva2:126834
QC 20100901Available from: 2008-11-26 Created: 2008-11-24 Last updated: 2010-09-13Bibliographically approved
In thesis
1. Bio-inspired cellulose nanocomposites and foams based on starch matrix
Open this publication in new window or tab >>Bio-inspired cellulose nanocomposites and foams based on starch matrix
2008 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

In 2007 the production of expanded polystyrene (EPS) in the world was over 4 million tonnes and is expected to grow at 6 percent per year. With the increased concern about environmental protection, alternative biodegradable materials from renewable resources are of interest. The present doctoral thesis work successfully demonstrates that starch-based foams with mechanical properties similar to EPS can be obtained by reinforcing the cell-walls in the foams with cellulose nanofibers (MFC).

High cellulose nanofiber content nanocomposites with a highly plasticized (50/50) glycerol-amylopectin starch matrix are successfully prepared by solvent-casting due to the high compatibility between starch and MFC. At 70 wt% MFC, the nanocomposites show a remarkable combination of high tensile strength, modulus and strain to failure, and consequently very high work to fracture. The interesting combination of properties are due to good dispersion of nanofibers, the MFC network, nanofiber and matrix properties and favorable nanofiber-matrix interaction.

The moisture sorption kinetics (30% RH) in glycerol plasticized and pure amylopectin film reinforced with cellulose nanofibers must be modeled using a moisture concentration-dependent diffusivity in most cases. The presence of cellulose nanofibers has a strong reducing effect on the moisture diffusivity. The decrease in zero-concentration diffusivity with increasing nanofiber content could be due to geometrical impedance, strong starch-MFC molecular interaction and constrained swelling due to the cellulose nanofiber network present.

Novel biomimetic starch-based nanocomposite foams with MFC contents up to 40 wt% are successfully prepared by freeze-drying. The hierarchically structured nanocomposite foams show significant increase in mechanical properties in compression compared to neat starch foam. Still, better control of the cell structure could further improve the mechanical properties. The effect of cell wall composition, freeze-drying temperature and freezing temperature on the resulting cell structure are therefore investigated. The freeze-drying temperature is critical in order to avoid cell structure collapse. By changing the starch content, the cell size, anisotropy ratio and ratio between open and closed cells can be altered. A decrease in freezing temperature decreases the cell size and increases the anisotropy ratio.

Finally, mechanical properties obtained in compression for a 30 wt% MFC foam prepared by freeze-drying demonstrates comparable properties (Young's modulus and yield strength) to expanded polystyrene at 50% RH and similar relative density. This is due to the reinforcing cellulose nanofiber network within the cell walls.

Place, publisher, year, edition, pages
Stockholm: KTH, 2008. viii, 50 p.
Trita-CHE-Report, ISSN 1654-1081 ; 2008:75
starch, cellulose nanofibers, foam, nanocomposites, cushioning materials, biodegradable, expanded polystyrene, mechanical properties, diffusion
National Category
Polymer Chemistry
urn:nbn:se:kth:diva-9666 (URN)978-91-7415-189-3 (ISBN)
Public defence
2008-12-16, F3, Lindstedrsvägen 26, Stockholm, 10:00 (English)
QC 20100913Available from: 2008-12-03 Created: 2008-11-26 Last updated: 2011-09-05Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Svagan, AnnaAzizi Samir, My A. S.Berglund, Lars A.
By organisation
In the same journal
Advanced Materials
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 188 hits
ReferencesLink to record
Permanent link

Direct link