Daisuke Ishii - Viscoelastic Evaluation of Average Length of Cellulose Nanofibers Prepared by TEMPO-Mediated Oxidation

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      Publication Details (including relevant citation   information):

    Biomacromolecules201112 (3), pp 548–550
    DOI: 10.1021/bm1013876
    Publication Date (Web): January 24, 2011

      Abstract:

        Dynamic viscoelasticity measurements were performed for aqueous   dispersions of cellulose nanofibers prepared by TEMPO   (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation   and subsequent mechanical disintegration in water. The frequency   dependence of the storage and loss moduli of 0.02% (w/v)   dispersions of TEMPO-oxidized cellulose nanofibers in water   showed terminal relaxation behavior at relatively lower angular   frequencies. This strongly suggests that each cellulose nanofiber   in the dispersion behaves as a semiflexible rod-like   macromolecular chain or colloidal particle. Furthermore, a clear   boundary was observed between the terminal relaxation and rubbery   plateau regions. The longest viscoelastic relaxation time, τ, was   estimated from the angular frequency, corresponding to the   boundary point, and the average length of the cellulose   nanofibers, L,   was estimated using the equation τ = πηsL3/[18kBT ln(L/d)].   The equation gave a value of L =   2.2 μm, which was in good agreement with TEM observations.

      Address (URL): http://pubs.acs.org/doi/abs/10.1021/bm1013876