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On the dissolution state of cellulose in cold alkali solutions

Author:
  • Joel Hagman
  • Luigi Gentile
  • Christian Moestrup Jessen
  • Manja Behrens
  • Karl-Erik Bergquist
  • Ulf Olsson
Publishing year: 2017-03-30
Language: English
Pages: 2003-2015
Publication/Series: Cellulose
Document type: Journal article
Publisher: Springer

Abstract english

We have characterized the dissolved state of microcrystalline cellulose (MCC) in cold alkali [2.0 M NaOH(aq)] solutions using a combination of small angle X-ray (SAXS) and static light scattering (SLS), (Formula presented.)H NMR, NMR self-diffusion, and rheology experiments. NMR and SAXS data demonstrate that the cellulose is fully molecularly dissolved. SLS, however, shows the presence of large concentration fluctuations in the solution, consistent with significant attractive cellulose-cellulose interactions. The scattering data are consistent with fractal cellulose aggregates of micrometre size having a mass fractal dimension (Formula presented.). At 25(Formula presented.) the solution structure remains unchanged on the time scale of weeks. However, upon heating the solutions above 35(Formula presented.) additional aggregation occurs on the time scale of minutes. Decreasing or increasing the NaOH concentration away from the “optimum” 2 M also leads to additional aggregation. This is seen as an increase of the SAXS intensity at lower q values. Addition of urea (1.8 and 3.6 M, respectively) does not significantly influence the solution structure. With these examples, we will discuss how scattering methods can be used to assess the quality of solvents for cellulose.

Keywords

  • Polymer Chemistry
  • Aggregation
  • Co-solvent
  • Cold alkali (NaOH)
  • Microcrystalline cellulose (MCC)
  • NMR
  • Rheology
  • Small angle X-ray scattering (SAXS)
  • Static light scattering (SLS)
  • Temperature dependence
  • Urea

Other

Published
  • ISSN: 0969-0239
Luigi Gentile
E-mail: luigi [dot] gentile [at] fkem1 [dot] lu [dot] se

Researcher

MEMEG

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Sölvegatan 37, Lund

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Visiting research fellow

Physical Chemistry

+46 46 222 45 04

1

Research group

Microbial Ecology

Projects

MICCS