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On the dissolution state of cellulose in cold alkali solutions

Hagman, Joel LU ; Gentile, Luigi LU ; Jessen, Christian Moestrup; Behrens, Manja LU ; Bergquist, Karl-Erik LU and Olsson, Ulf LU (2017) In Cellulose p.2003-2015
Abstract

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... (More)

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.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Aggregation, Co-solvent, Cold alkali (NaOH), Microcrystalline cellulose (MCC), NMR, Rheology, Small angle X-ray scattering (SAXS), Static light scattering (SLS), Temperature dependence, Urea
in
Cellulose
pages
13 pages
publisher
Springer
external identifiers
  • scopus:85016464054
  • wos:000399233400007
ISSN
0969-0239
DOI
10.1007/s10570-017-1272-3
language
English
LU publication?
yes
id
819500dd-9914-4860-a2a2-b4e2beae8206
date added to LUP
2017-04-12 11:58:18
date last changed
2017-09-18 13:32:21
@article{819500dd-9914-4860-a2a2-b4e2beae8206,
  abstract     = {<p>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.</p>},
  author       = {Hagman, Joel and Gentile, Luigi and Jessen, Christian Moestrup and Behrens, Manja and Bergquist, Karl-Erik and Olsson, Ulf},
  issn         = {0969-0239},
  keyword      = {Aggregation,Co-solvent,Cold alkali (NaOH),Microcrystalline cellulose (MCC),NMR,Rheology,Small angle X-ray scattering (SAXS),Static light scattering (SLS),Temperature dependence,Urea},
  language     = {eng},
  month        = {03},
  pages        = {2003--2015},
  publisher    = {Springer},
  series       = {Cellulose},
  title        = {On the dissolution state of cellulose in cold alkali solutions},
  url          = {http://dx.doi.org/10.1007/s10570-017-1272-3},
  year         = {2017},
}