New simulation approach to mechanical properties of nanocellulose aerogels

Joonas Sorvari, Jukka Ketoja, Nikolai Beletski, Jenni Sievänen, Hans-Peter Hentze, Aki Kallonen, Marko Peura, Ritva Serimaa

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    Abstract

    Highly porous, mechanically stable aerogels were prepared by freeze drying of nano-fibrillar-cellulose (NFC) suspensions. The NFC concentration was varied to alter the morphological structure and mechanical properties of the samples. Three dimensional samples were prepared and their compressibility was tested. The increase of NFC content and thus density clearly increased the mechanical strength. The pore morphology of the structures was investigated with SEM and X-ray tomography. The main feature in the structures was the formation of micron-sized nanocellulose sheets. From the 3D tomography image, we obtained 2D cross-sections that allowed the recording of microscopic geometric features. This structure was used to simulate the stresses and strains during compression with a rigid surface. The model considered a microscopic 2D structure formed from thin beams representing the NFC sheet-like layers. The microscopic model was implemented in a commercial FE-code. We also simulated similar artificial structures obtained by placing beams randomly in a rectangular cell. The resulting stress-strain curves were consistent with experimental findings. The sheet-like layers improve effectively the stiffness of the structures.
    Original languageEnglish
    Title of host publicationInternational Conference on Nanotechnology for the Forest Products Industry 2010
    PublisherTAPPI Press
    Pages759-776
    Volume2
    ISBN (Print)978-1-61839-001-1
    Publication statusPublished - 2010
    MoE publication typeA4 Article in a conference publication
    Event2010 TAPPI International Conference on Nanotechnology for the Forest Product Industry - Dipoli Congress Centre, Espoo, Finland
    Duration: 27 Sep 201029 Sep 2010
    Conference number: 5

    Conference

    Conference2010 TAPPI International Conference on Nanotechnology for the Forest Product Industry
    Country/TerritoryFinland
    CityEspoo
    Period27/09/1029/09/10

    Keywords

    • aerogel
    • cellulose
    • nanofiber
    • modelling
    • simulation
    • mechanical properties
    • stiffness
    • deformation

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